Might Guy

is a jōnin of Konohagakure. A master of taijutsu, Guy leads and passes his wisdom to the members of Team Guy.

Background
During Guy's early childhood, his performance in the Academy was below average, ultimately failing his first attempt to enter it. When he finally managed to pass his entrance exam, he continued to show little skill in ninjutsu and genjutsu. Because of this and his admiration for his father, Might Dai, who was a proficient user of hand-to-hand combat, Guy developed a great passion for taijutsu. Guy would frequently train to impress his father, despite his father being only a genin. On one occasion, Guy became frustrated with his father being mocked and attacked two older ninja, only to end up in the hospital.

When Guy began despairing that he might never become a good ninja and remain a genin himself due to his lack of talent, Dai decided to teach Guy the Eight Gates, under the pretence that he should only do so if he was protecting something or someone. Later, during a mission, Guy and his team-mates were attacked by the Seven Swordsman of the Mist and they were saved by Dai, who later died because of opening all the inner gates to protect them and give them enough time to escape. When Guy first took the Chūnin Exams, he was placed in a team with Ebisu and Genma Shiranui. During the second stage of the exams in the Forest of Death, Guy's team came face-to-face with Team Minato. Before Obito, who had taken the lead, could attack them, Guy unceremoniously kicked Obito in the face, inadvertently saving the boy from choking on a sweet. During the third stage of his first Chūnin Exams, Guy faced Obito once again where after trying to give Obito the nice guy pose was met with a thumbs-down. Though Guy defeated Obito, he faced his own loss against Kakashi Hatake in the next round.

After losing to Kakashi, Guy began to see Kakashi as his sworn rival. In the anime, Guy first approached Kakashi while he was reading and quickly announced his desire to challenge him. While initially Kakashi was completely indifferent to the overzealous Guy's request, Guy continued to follow Kakashi around and challenge him. Eventually, Kakashi gave in to Guy's request, beating Guy in every challenge, including various forms of marksmanship, taijutsu combat, and even physical comparison. Despite these losses, Guy became only more determined to defeat Kakashi. Seemingly warming up to Guy, he continued to accept Guy's various challenges (including eating contests and Rock, Paper, Scissors), even when training with his team, ultimately giving Kakashi a record of 49 wins and 50 losses. After the events of Kannabi Bridge, Guy was assigned to a mission with Kakashi and Rin. With the situation looking grim, Guy used himself as a scapegoat to allow his comrades to escape but is soon joined by Kakashi. The two shinobi are eventually able to stave off the Iwa-nin until Rin returned with reinforcements. The events of this mission would cause the two to build great trust in one another and a strong friendship despite their civil rivalry. But regardless, Guy still competed regularly with Kakashi. Later, after Minato Namikaze was officially made Fourth Hokage, Kakashi was assigned to recover important documents that would help the delicate transition towards peace between Konoha and Iwa. Fearing Kakashi's mental state after accidentally killing Rin, Minato sent Might Guy and some Anbu as secret backup for Kakashi. This ultimately proved a wise decision as Kakashi soon collapsed in hyperventilation when he engaged an enemy as he prepared his Chidori. Guy quickly intercepted the enemy to save Kakashi and brought his rival back to Konoha to recover. Seven years after the Nine-Tails' attack, watching Kakashi continue to sink deeper into self-imposed isolation, Guy approached the Third Hokage in the hopes of joining Kakashi in Anbu. Guy's request was refused under the grounds that Guy's attributes were not suited to the duties of Anbu, something Danzō Shimura agreed to, noting that Guy lacked the necessary darkness. Later, Guy was assigned to deliver a scroll to ninja of the Land of Woods for a potential alliance. Despite a mission of peace, Guy quickly realised this mission was actually a test of honesty on the Land of Woods' part. Upon meeting the Wood-nin, Guy's suspicions proved correct as Guy's team was deceived and saved by Guy's quick acting attack. As Guy's team was surrounded by several Wood-nin, Kakashi and Itachi Uchiha, a new and young recruit in Kakashi's unit, appeared and swiftly defeated the enemies. As Guy watched in horror as his friend and rival mercilessly killed the defenceless Wood-nin, Guy began to understand what Danzō meant before. Returning to the village, Guy agreed with Hiruzen that he wasn't suited for Anbu, but also insisted to the Hokage that Kakashi wasn't either.

During Nine-Tails' attack on the village, Guy was among the young ninja barred from participating in the defence of the village by Kurenai's father and other older shinobi. In later years, before Guy became a jōnin-sensei, he heard rumours of an Academy student that was determined to become a ninja despite every indication that he couldn't. When this student, Rock Lee, eventually became his own student, Guy became determined to help Lee become a taijutsu master, as Lee did not have the skill to use ninjutsu or genjutsu.

Personality
Known for his thick eyebrows, green jumpsuit, and shiny bowl haircut, Guy often refers to himself as. He has many mannerisms unique to him in the series that are meant to be seen as corny and old-fashioned, a reference to common clichés of in the anime. Guy is also known for going on about the "Power of Youth".

Guy has problems remembering the faces of persons he does not interact with frequently, best seen in his fights with Kisame Hoshigaki, his fight with the Three Ryūdōin Brothers, and even when fighting Madara Uchiha. Obito has mentioned this as a trait of Guy's. It was explained that this may be due to the fact that Guy always looks to the future instead of dwelling in the past.

Guy is best known for his "nice guy pose", which consists of giving a thumbs up, winking, and smiling with teeth so white they give the proverbial "ping". This action is often used by both Guy and Lee to indicate commitment to a statement they had just made, their highest form of a promise. It is suggested that Guy got the idea for the "nice guy" pose from his battle with Obito Uchiha during the Chūnin Exams. Despite these odd mannerisms, Guy has shown to be capable of being as serious, ruthless and decisive as a mission's success demands if needed, as seen during the Invasion of Konoha and his battles with Kisame Hoshigaki. Despite his seemingly oblivious nature at time, Guy can be very attentive to the situation at hand. During a mission of diplomacy, Guy was able to deduce its true purpose as a test of loyalty, a feat which astounded a young Itachi Uchiha. He is noted to be quite scary if switching to "serious", but very reliable.

Guy is on good terms with all of his students, but takes particular interest in Rock Lee, who reminds Guy of himself in his youth in retrospect that both are considered losers and have to work hard to achieve their goals. As such, Guy puts much more interest in Lee's training than Neji's or Tenten's, continuing to train Lee long after the others have retired for the day. Because of this, and due to Lee's unyielding desire to master the art of taijutsu, the two have developed a father-son relation that has pushed Guy to teach Lee a number of dangerous and forbidden techniques, giving the stipulation that Lee can only use them under specific circumstances. Although Guy knows of the dangers that teaching the techniques to Lee entails, Guy wishes for Lee to be able to prove himself to be a splendid ninja, and, as such, turns a blind eye to the repercussions. However, overall, Guy is a very attentive and dedicated instructor, who does everything in his power to make sure that all three of his prized students receive proper instruction in their own particular fields.

Guy, and, by extension Lee, lives his life by his own "My Rules" philosophy, which involves setting tougher goals for failure so something good comes of it. For example, he vowed to walk 500 laps around Konoha on his hands if he lost a simple game of rock, paper, scissors with Kakashi, and proceeded to do so upon losing, even though people stopped paying attention eventually. Lee's willingness to train in the same manner as Guy seems to have caused him to surpass his master's stamina, as by the end of Part I, Guy has difficulty keeping up with Lee, lamenting that he is not as youthful as he once was. During his early childhood, Guy's personality was quite the opposite; he suffered much insecurity from his lack of natural talent and was greatly concerned about other people's opinions.

Guy's teacher-student relationship with Lee also carries distinct attributes, such as when Guy will punch Lee for a slight infraction of a rule. After Guy assigns Lee an arduous training task as punishment, meant to recapture Lee's focus and discipline, the two may then burst into tears and affectionately embrace, in brief regret for the strong blow Lee was given. Guy often attempts to act in a similar way towards his other two students, although Tenten is usually resigned and more willing to take part in his antics than the more stoic Neji.

Guy is the self-proclaimed rival of Kakashi Hatake, though the latter is indifferent to the former's annoyance. Since first losing to Kakashi during the Chūnin Exam, Guy randomly challenges Kakashi to contests of skill, and has acquired a record of 50 wins and 49 losses in doing so (50 wins and 51 losses in the anime). Given that the contests that make up this figure are so varied (ranging from Rock, Paper, Scissors to running races), this is not much of an achievement on Guy's part nor an accurate comparison of respective combat power. Nevertheless, Guy is proud of his record. Their competitions seem to, in part, be founded on the fact that the two are polar opposites. Guy has shown to be more easily excited compared to the more laid back Kakashi. He also relies mainly on taijutsu, in contrast to Kakashi's ninjutsu specialisation, and had to work tremendously hard to reach his level of prowess, whereas Kakashi's natural talent and Sharingan made it easier for him to improve. Nevertheless, both men are great friends and also have the utmost faith in each other seen during the Fourth Shinobi World War when they entrusted the protection of their blind spots to each other. This was also expanded on in the anime, where Kakashi told Tsunade that he would need a second-in-command during the war and wanted Guy to serve that purpose. Guy's and Kakashi's level of friendship was such that when faced with five fully transformed tailed beasts preparing to fire their Tailed Beast Ball in close proximity, he was more than willing to activate the last of the Eight Gates to protect Kakashi, despite the fatal repercussions.

Guy can't handle sea rides and easily gets seasick when he has to travel by boat or ship. After getting over this and attempting the challenge at the Falls of Truth, Guy's "inner self" rebuked him for being too old yet still maintaining a hyper-active demeanour, adding that it is not healthy for old men like him to push themselves so hard.

Appearance
Guy is a tall and well-built man with high cheek-bones, thick eyebrows and black hair cut in a bowl style. Guy wears a green jumpsuit, orange striped leg warmers and the standard Konoha flak jacket, though it's normally unzipped and has only been seen zipped up during the Fourth Shinobi World War. His forehead protector, is on a red cloth and is worn around his waist, like a belt. When he was a genin, he wore the same style of clothing with bandages wrapped around his hand and a brown scarf tied around his neck. His hair also had the shape of his signature bowl-style though a bit longer and shaggier, framing the side of his face. When he became a chūnin, he donned the flak jacket, got his signature haircut and also removed the scarf.

His protégé Rock Lee has modelled his appearance after Guy and as such both men bear a striking resemblance: both naturally having thick eyebrows and the same hair cut.

Abilities
Despite a poor start in his ninja career, considering himself a loser as a child, the famous Sakumo Hatake openly acknowledged Guy's potential growth. Guy ultimately became a very powerful shinobi, graduating from the Academy at age 7, becoming a chūnin at age 11, and recognised as one of Konoha's strongest. Itachi Uchiha warned others against underestimating Guy. This coming from such a powerful ninja is an indicator that Guy is an excellent combatant. A testament to his skill as a ninja was him single-handedly defeating the extremely dangerous Akatsuki member, Kisame Hoshigaki. This is later reaffirmed when Kakashi Hatake trusts him to take on the Six-Tails alone during their battle with the reincarnated jinchūriki. Even as the Ten-Tails' jinchūriki, Madara Uchiha acknowledged Guy's capabilities, expressing how much he enjoyed the battle and openly admitted that Guy almost killed him with his final attack.

Taijutsu
During childhood, Might Guy had a very low talent in ninjutsu and genjutsu, so he focused solely on taijutsu like his father. Might Dai saw this as an opportunity to teach him his own strengths and weaknesses. This in turn gave Guy a chance to focus on his own "virtues" that other kids of his age cannot do. As an adult, Might Guy is an extremely accomplished taijutsu master, with advanced knowledge, if not skill, in various taijutsu styles and techniques. As noted by Kisame Hoshigaki, it is very rare for one to reach Guy's level of prowess; Madara Uchiha stated that Guy's taijutsu prowess is of the highest level possible.

Through his "My Rule" philosophy, which involves a series of extreme and unorthodox training regimes, Guy has gained a strong and enduring body with immense reserves of chakra and stamina by constantly pushing his own limits. This allows him to recover from extreme exhaustion in an alarmingly short period of time and utilise the style known as "Strong Fist" to its full potential. In addition, his intense training has given him such tremendous speed that his movements can seem like he's disappearing to unfocused eyes, and strength capable of easily ploughing a full-grown man through a solid stone wall and through the air with a single hand: accomplishing both feats without the aid of chakra-enhancement. It was even shown in Part I that he was capable of repelling Gaara's sand attack with a single hand.

Eight Gates
Guy is able to utilise and open all of the Eight Gates — a feat that is difficult for even some of the most talented ninja. His knowledge and understanding of this ability allowed Guy to teach others to access multiple gates. Once accessing all eight gates, he is able to fight on par with and gradually overwhelm Madara Uchiha as the Ten-Tails' jinchūriki, significantly damaging the Uchiha who compares this power to fighting Hashirama Senju. Because of the potential harm opening the gates can cause the user, Guy has decided that he will only open the gates if it is a life-or-death situation, or he is protecting someone dear to him. However, Guy's extremely intense training routines has allowed him to handle opening the gates for longer periods of time, able to endure the sixth gate with only noticeable exhaustion, as well as resist the after-effects of the seventh gate to continue fighting for a short period. By the Fourth Great Shinobi War, Guy became able to withstand using the seventh gate repeatedly with only momentary exhaustion.

His mastery is enough that he is capable of utilising several kinjutsu after opening the gates, making him truly a formidable force on the battlefield. With the first gate, Guy can use the pile-driving Front Lotus and with the third gate, Guy can use the more advanced Reverse Lotus. When opening the sixth gate, Guy can utilise the Morning Peacock, a technique so fast that his hands were set ablaze by sheer speed and friction. When unlocking the seventh gate, he can utilise a one-hit kill technique called Daytime Tiger, which is strong enough to completely overwhelm Madara Uchiha's complete Susanoo and reduce a shinobi as strong as Kisame Hoshigaki to near immobility. Once opening the eighth and final gate, his speed becomes enough to catch Madara in his Ten-Tails' jinchūriki form off-guard and is able to propel himself through the air with his kicks, creating a pseudo form of flight. With the eighth gate, he is able to use the Evening Elephant, a technique that gives his strikes such force, even consecutively, they can create powerful shockwaves that cannot be dodged and are nearly impossible to block. His final Eight Gates attack, the Night Guy, is a technique that, after gathering an extraordinary amount of chakra in the form of a dragon-like aura, launches a kick of such ferocity and speed that it distorts the space around him, and is capable of obliterating his target upon impact. The technique is so powerful that it shattered Madara Uchiha's ribs, along with Guy's own leg, and nearly killed them both, leaving a gaping hole in the former's body.

Bukijutsu
Aside from his taijutsu repertoire, Guy is also highly skilled in a variety of weapons styles, having trained Tenten extensively in their respective usages. His personal weapon of choice is the nunchaku, but only resorts to using them when absolutely necessary, and from what has been shown he uses them with great ferocity and power, matching Kisame's unique swordplay. Aside from his regular set, Guy keeps a second, special pair of nunchaku with him, called the Sōshūga, which he used to skilfully battle Obito. These were durable enough to smash a large rock into pieces, and trade blows with Obito's gunbai.

Other Skills
Despite his early shortcomings in ninjutsu and genjutsu, Guy later developed at least capable abilities in the two skills, able to dispel a high-level genjutsu, and summon nin-tortoises like Ningame or (in the anime) a much smaller messenger tortoise to deliver messages. Guy is at least knowledgeable of powerful techniques, recognising and commenting on the Four Red Yang Formation during the Fourth Shinobi World War. Regardless, Guy makes a conscious effort to rely almost exclusively on taijutsu; even using regular disguises instead of the Transformation Technique.

In his rivalry with Kakashi, Guy has developed an effective counter against Sharingan-users: by focusing on the positioning of their feet, Guy can both predict the movements of the enemy and negate the Sharingan's necessity of having eye-contact for genjutsu techniques. Currently, Guy is the only ninja who can use this technique, though he has taught the basics of it to Asuma, Kurenai, and also Kakashi. In the anime, it is shown that Might Guy is knowledgeable in herbal remedies, regularly preparing them for Lee to help further his training.

Chūnin Exam Arc
Guy made his début shortly before the start of the Chūnin Exams, stopping Lee from using the Front Lotus on Sasuke Uchiha. He punished Lee for attempting to use a forbidden technique before having an emotional embrace with him, much to Team 7's disgust. He appeared again during the preliminaries to watch his students' matches. He showed anger at Temari's treatment of Tenten after their match, and disappointment with Neji when he tried to kill Hinata Hyūga, having earlier instructed him to not make the match into a vendetta with the Hyūga clan.

Guy then took the role of Lee's coach prior to his match with Gaara, giving him general advice on what to do. During the actual fight, Lee continually found his fighting level to be inadequate in defeating Gaara, and each time Guy gave his consent for Lee to increase the strength of his attacks. When Lee began to run out of options, Guy allowed Lee to open the first five chakra gates in order to defeat Gaara. Although Lee did so, his efforts were unsuccessful, and he was left heavily injured. When Gaara was about to kill Lee, Guy stepped in to stop the match, not willing to allow anything to happen to Lee. As Lee was taken away to be healed, one of the medics informed Guy that the injuries to Lee's body were so severe that he would never be able to fight as a ninja again. Guy was crushed by this prospect, and regretted ever teaching Lee so many dangerous techniques.

Invasion of Konoha Arc
A month later, when Gaara tried to finish off a hospitalised Lee, Guy once again intervened to save his beloved student. When Lee recuperated to the point of being able to watch other matches, Guy accompanied him to the final round matches, only to be surprised that Neji was defeated by Naruto Uzumaki. He later marvelled at Sasuke's ability to have replicated Lee's base speed from their sole encounter, but noted that it was much more crass than Lee's. When Sasuke unveils the Chidori, it confirms Guy's suspicions as the reason why Kakashi had Sasuke replicate Lee's speed, though he is criticised for what his training did to Lee after Guy tried to criticise Kakashi for the same reason of teaching his student a dangerous technique.

When the invasion of Konoha began, Guy wanted at first to aid the Third Hokage, but instead teamed up with Kakashi in repelling the invading forces and protecting the unconscious spectators. Despite the seriousness of the situation, Guy still made clear that he was considering this another challenge against Kakashi over who could take out the most enemy ninja. After Kakashi gives orders to Sakura Haruno, Naruto Uzumaki, Shikamaru Nara and Pakkun to go after Sasuke Uchiha, Guy intercepts an Oto-nin and uses him to create a hole in the wall of the arena, effectively giving the genin an exit. He later attended the Third's funeral.

Search for Tsunade Arc
When Kakashi was about to be defeated by Akatsuki members Itachi Uchiha and Kisame Hoshigaki, Guy arrived in time to repel Kisame and save Kakashi. When Guy stated that he had called for back-up, the two left, unwilling to start a war. Guy got Kakashi medical attention, before following the two. When he finally caught up to them, he made an attempt at a sneak attack in order to avoid Itachi's Sharingan. In doing so, he accidentally attacked Jiraiya, Itachi and Kisame having already left. After apologising for his mistake, Guy learned that Jiraiya was looking for the talented medical ninja Tsunade, and asked that Jiraiya be sure to find her, in the hopes that she would be able to heal Lee. Before leaving for Konoha with an unconscious Sasuke Uchiha, he gave Naruto his spare green jumpsuit, as a reward for his determination. Jiraiya was, naturally, unsettled by this, but Naruto was ecstatic.

Once Tsunade was found, and returned to Konoha, she found that the operation that would heal Lee had a 50% chance of death. Although Lee was reluctant to risk his life, since that would mean he couldn't be a ninja, Guy convinced Lee to go through with the operation, saying that all the work Lee had done meant that he would definitely survive. In the event that Lee did die during the operation, Guy said that he would die too, as he had no point in living if he couldn't help Lee become a great ninja. Lee's operation was a success, and Guy visited him daily until he was ready to start training again.

Pre-Shippūden Filler Arcs
In the anime, Guy was the only jōnin to receive a considerable amount of screen time.

When Lee's dōjō went unchallenged in one arc, Guy challenged Lee himself disguised as a stranger. Although the disguise was very bad, Lee never caught on that it was actually Guy.

In the Third Great Beast Arc, Guy began training a visiting ninja named Yagura. Yagura trapped Guy and Lee in a castle together, and forced them to fight each other through artificial, mute proxies - they figured this out by communicating through Morse code, then broke out by opening the first five gates, the stress of their high-speed attacks causing the constructions to break apart.

Later, in the Trap Master Arc, Guy led Konoha's available jōnin to stop a suspected invasion by Takigakure, though in reality the Takigakure forces were just having a training exercise.

Kazekage Rescue Arc
Team Guy was assigned by Tsunade as back-up to assist Team 7 in rescuing Gaara. On their way to meet Team 7, Guy again encountered Kisame Hoshigaki, who wanted to take revenge on Guy for hitting him during their last encounter. Guy, however, didn't seem to remember Kisame, which greatly agitated the Akatsuki member. Kisame was strong enough to overcome the entire Team Guy, but when he succeeded in imprisoning Guy's students in respective water prisons and nearly drowned Tenten, Guy opened the sixth chakra gate and used his Morning Peacock to defeat Kisame. As the group examined Kisame's corpse, they found that it was not Kisame, but merely a body double; namely a former Sunagakure ninja called Mukade.

Upon reuniting with Team 7 and reaching the Akatsuki hideout, Team Guy was assigned to disable a barrier surrounding the hideout's entrance. Although they completed the task, they were forced to fight clones of themselves, though each member eventually succeeded in defeating their lookalikes. Returning to Team Kakashi, Guy and his students uncover Deidara hiding in the bushes. Confronting the Akatsuki member, who subsequently escapes, the shinobi are forced to run for cover when their opponent seemingly committed suicide. Kakashi, however, was able to warp the blast away using Kamui. After Gaara was rescued, Guy carried Kakashi back to Konoha on his back, because the latter was too exhausted to walk there under his own power due to his overuse of Mangekyō Sharingan. Their students were deeply irritated by the disturbing sight, although Guy didn't seem to notice, and instead had a race with Lee to see who could reach Konoha first.

Sasuke and Sai Arc
In the anime, he and his team appear in the very beginning of this arc.

Hidan and Kakuzu Arc
In the anime, he was seen standing beside Kakashi, mourning Asuma Sarutobi's death.

Invasion of Pain Arc
When Pain's invasion of Konoha began, Team Guy was away on a mission. During a pit-stop on their return home, they noticed a number of birds apparently escaping from the village. They rushed to the village, and found it to be in ruins. They found Hinata Hyūga badly injured, and got her medical attention. After the team finds Hinata, Katsuyu later informs them that Naruto was fighting with the last Pain and Guy insists that he and his team should provide back-up, but Katsuyu mentions that Naruto does not want anyone else to get involved, which angers Guy. They were then later present with the other villagers celebrating Naruto's defeat of Pain.

Chikara Arc
In the anime, upon receiving news that Kabuto Yakushi is responsible for the massacre in Tonika Village, Tsunade sends Guy, Kakashi, and Shikamaru Nara to assist Team Kakashi.

Confining the Jinchūriki Arc
The group eventually made it to their destination in the Land of Lightning. Once Guy recovered from his seasickness, he asked Motoi to help them locate Naruto. Motoi took him and Aoba to the Falls of Truth, explaining that Naruto began his training to conquer the Nine-Tails by sparring with his inner-self. Interested in going through the same training, Guy approached the falls. As his "true-self" began to manifest it mocked his ideology of youthfulness, saying that "Old men shouldn't push themselves so hard". What finally emerges was apparently a blowfish, but in reality Kisame Hoshigaki. Guy immediately attacked him, knocking him into the falls.

Guy once again could not remember meeting Kisame before. He nevertheless recognised that Kisame was a threat and pursued him as he tried to escape the island. He first had Killer B fling him across the island, and then summoned Ningame mid-flight to provide him a stepping stone. He found Kisame trying to send intel he had gathered to Akatsuki by way of shark. To mask the shark's movement, Kisame created a thousand more, which Guy attempted to stop with the Morning Peacock. When he was unable to stop all of the sharks, Guy was forced to open the Seventh Gate: Gate of Wonder in order to match Kisame's Water Release: Great Shark Bullet Technique with his Daytime Tiger. When the two massive techniques clash, Guy's Daytime Tiger went right through the Great Shark Missile and hit Kisame dead on, erupting into a massive shock wave large and powerful enough to have its after effects be felt some distance away.

The Konoha ninja restrained Kisame and tried to gather intel about Akatsuki from him, but he broke free of his bindings and committed suicide to prevent them from interrogating him. Seeing how far Kisame was willing to go for his comrades, Guy gained new respect for his adversary and vowed to always remember him. Hoping that the intel Kisame had would reveal something they examined it, only to be caught in water prisons with sharks. Guy, finally experiencing the side-effects from the seventh gate, was unable to defend himself, but was saved by the others.

Shinobi World War Arc
When the Fourth Shinobi World War began, Guy was placed in the Third Division under Kakashi's command. Still suffering from the effects of opening the Seventh Gate, Sakura healed him as a concerned Lee looked on. He recovered by the time the Third Division comes to the aid of the Surprise Attack Division, restraining Gari when they first arrived.

When fighting broke out with Akatsuki's reincarnated ninja, Guy teamed up with Lee to defend members of the division from Haku. Prior to returning to the fight, Guy reminded the troops not to lose their resolve when friends die but to turn their death into the life of another. In the anime, after the Seven Ninja Swordsmen of the Mist were summoned, Guy told Lee to chase after Pakura, while he went after Gari. Guy later regrouped with the rest of his division to recuperate in a forest, as night fell.

In the anime, as the battle resumes the next day, Guy aid Kakashi in battle with Kushimaru Kuriarare and Jinpachi Munashi. Later, he informed Kakashi,after Fuguki Suikazan was sealed, that there were only three reincarnated shinobi left on the battlefield. Upon seeing the new wave of White Zetsu Army forces approaching them, Guy told Kakashi that they should defeat them in one fell swoop while at the same time, Naruto's shadow clone appeared on the battlefield to aid them.

Later, Guy's division was attacked by a famous reincarnated taijutsu master named Chen. Exciting at the idea of facing the legendary hero, Guy formally challenged the reincarnated shinobi to battle. The two taijutsu masters initially fought evenly, but Chen's tireless reincarnated body soon overwhelmed Guy. When Rock arrived to aid Guy, both Lee and Chen were surprised to see each other. After hearing the story of how Chen and Lee met, Guy was outraged to hear Chen tried to make Lee quit being a shinobi. While he admitted that Chen's views weren't wrong, it was still Lee's own personal dream. Feeling he had to prove his point once and for all, Chen attacked the teacher and pupil with his Leaf Dragon God. To Chen's surprise, Lee revealed to have learned the weakness of Chen's technique and defeated it. Amazed at how far Lee came solely with taijutsu and the bond that he had with Guy as a teacher, Chen admitted to his own faults with his student, ashamed to have not had more faith in him. Finally letting go of his past pain, Chen broke the summoning contract and returned to the afterlife.

After sealing the final Swordsman, Guy and Kakashi made their way to Naruto and B's battlefield in time to stop Tobi from warping Naruto away. Guy uses his Violent — Leaf Adamantine-Strength Whirlwind technique to force Tobi to become intangible while Kakashi retrieved Naruto. After being talked down to, Guy told Tobi not to underestimate him as he was Konoha's Sublime Green Beast of Prey. He then told Naruto to calm down as his explanation of the situation was jumbled, before destroying the coral covering Naruto's body. As the tailed beasts attacked again, Guy told Kakashi that he wasn't good with faces, and they all looked the same to him before opening the Sixth Gate as he, and Kakashi begin their counter-attack. As Kakashi wondered why the reincarnated opposition weren't using the regular abilities of the Six Paths of Pain, Guy stated that Tobi would most likely know that they had come up with counter measures against these abilities, so he wouldn't waste his time and chakra, having them use it.

As their battle with the tailed beasts continued, Guy noticed Naruto in the clutches of Son Gokū's mouth. Alerting Kakashi before springing into action, he was impeded by the the Six-Tails' corrosive gas bearing down on them at one end, and the tailed beast barricading them at the other. Turning back-to-back as Kakashi creates a shadow clone in the Manji Formation, the men entrust their backs to each other as they face the enemy in front of them. As Guy rushed towards the gas he uses the Morning Peacock technique to burn off the gaseous attack and prepared for the next wave of attacks. As Naruto succeeded in releasing Son from Tobi's control, both Kakashi and Guy look on, shocked, as the now fully-transformed jinchūriki bore down on them.

As the situation became dire, Guy stated that there was no option but for him to use the Eighth Gate after telling Kakashi that there was no way he would have enough strength to warp away the five Tailed Beast Balls that were aimed at them, but Kakashi also dismissed Guy's suggestion, stating he would die after opening that gate. Both men are rescued, however, by Naruto, entering a new mode and deflecting the attacks. Absorbed into the Nine-Tails' chakra as Naruto transformed, both men watch on as the battle between the beasts ensued. Guy later noted that it looked like a scene from the Destroy All Monsters film.

After Naruto's Tailed Beast Mode is cancelled, and the men stand alongside Naruto, facing the opposition, Guy stated that seeing Naruto come so far made him feel old. Somewhat shocked, Kakashi was the one to tell him that their youth wasn't over yet. Guy then stopped Kakashi mid-sentence, saying that he was making him feel even older. He later mobilised alongside Kakashi, Naruto, and B in his full Eight-Tails form preparing to assault Tobi and the Demonic Statue of the Outer Path. Launching his assault after Kakashi and his shadow clone attacked the statue once again, Guy used his Little Toe Attack to crush the statue's foot sending it toppling over and straight into Naruto and B's uppercut attack all the while cheering Naruto on as he mocked Tobi against Kakashi's advisement.

Ten-Tails Revival Arc
Guy later noted that the statue had been acting weird ever since it swallowed the two objects in its mouth. After Naruto and Kurama switched in order for the beast to explain what was happening, Guy listened on before asking what the Treasured Tools of the Sage of the Six Paths and the Gold and Silver Brothers had to do with the current situation. After he heard Tobi chide Kakashi, telling him that he spoke too easily which was why he lived a life full of so much regret, Guy asked him who exactly he was but Tobi only responded stating that it wouldn't make any difference because Guy didn't remember faces. When Naruto retorted that dreams were essential, Guy added that even if you never want your youth to end, people had to stop dreaming some time or the other.

As the team prepared to attack Tobi directly, Guy noted that the use of feints would be crucial in this battle because of Tobi's abilities. Deciding that it was better to not attack him directly, Guy reaches into his pouch and retrieved his Sōshūga. Providing Naruto with backup, Guy was able to intercept one of Tobi's attacks which forced him to become intangible. Deflecting all of Tobi's attacks Guy was ultimately able to knock the masked man off his feet and send him hurling towards Naruto's Super Mini-Tailed Beast Ball. Shocked when Tobi disappeared, Guy tried to reach Naruto when the masked man reappeared but noted that the falling debris was becoming cumbersome. Later regrouping with his comrades, Guy asked them if they were okay before they wondered how they could defeat Tobi.

Noticing the small crack in Tobi's mask, Guy alerted Kakashi to the occurrence. Assuming that the crack was as a result of Naruto's last attack, Guy noted this but Kakashi disagreed noting that the crack wasn't concurrent with a punch. Obliging Kakashi's request to test out his hypothesis, Guy climbed aboard Gyūki's hand and is then launched across the battlefield towards Tobi. Confronting the masked man first, Guy uses his Sōshūga them to break the rock in front of him forcing Tobi to phase through them. Using the nunchaku Guy attacks the intangible masked man, provoking Tobi to become intangible and absorb them and as such, susceptible to Naruto's incoming attack. Guy later listened in shock as Kakashi revealed the mechanisms behind Tobi's technique.

Telling Kakashi to explain it as simply as possible and based off this, they would readjust their strategy, Guy and the others listened as Kakashi explained the mechanism behind Tobi's warping ability and intangibility. When B questioned why Kakashi's Sharingan was connected to Tobi's dimension, Guy hesitantly turns to Kakashi who questioned Tobi on where he got the eye. Shocked by the answer, Guy is later visibly angered when Tobi chastised Kakashi and shocked once again when Kurama spoke directly to Tobi before Naruto charged at the masked man in his Tailed Beast Mode. Shocked to see Naruto heading out on his own, Guy alerted Kakashi whom he soon realised was lost in deep thought. As he tried to get his comrade to focus, the two watch on as Naruto and B confronted the mask man. When Kakashi finally came around the two men charge at Tobi, with Guy remaining by Kakashi's side as he put his new strategy into action.

Alongside Kakashi, Guy who was supporting the latter after he had collapsed, was left completely stunned upon seeing that Tobi is Obito Uchiha. As a shocked Guy and Kakashi question the once masked man, their questions are greeted with indirect answers. Later when Obito attacks Guy and Kakashi, Guys calls out to his comrade who was seemingly frozen in shock. They are later further surprised by the arrival of Madara Uchiha to the battlefield. As the battle waged on, Guy aided Naruto in fighting the legendary Uchiha, and though bloodied and seemingly exhausted, he noted to Gyūki and B that it was because Madara was so strong that made it worth fighting him, which prompts the Eight-Tails to tell him that he should not push himself so hard. As the battle waged on, Guy realised that the Wood Dragon was absorbing Naruto's chakra, but before they could lend their aid, he and the Eight-Tails were bound by Madara and rendered immobile. As Madara was about to deal the finishing blow the attack was intercepted by Naruto. Hearing Naruto's speech to protect his comrades then spurred Guy on to use the Daytime Tiger to attack Madara, which sends the Uchiha flying away from them, prompting the Eight-Tails to acknowledge that Guy wasn't just acting tough.

When Kakashi noted that he had resolved to protect Naruto, Guy echoed his sentiments, and when the Wood Release had loosened its hold on Gyūki who was able to break itself and Guy free. As the process is completed and the Ten-Tails is resurrected, Kurama places Guy and Kakashi into his mouth, from which he restores the two shinobi's respective chakra. After Kurama is forced to retreat momentarily to gather more chakra, the remainder of the Allied Shinobi Forces arrive to their comrade's aid in time to deflect a point blank Tailed Beast Ball fired at their comrades. When Shizune arrived, she immediately began healing Guy who later stood with the rest of the Alliance, prepared to face the opposition.

Opening the Fifth Gate, Guy and his student prepare to attack the two Uchiha but are buffeted by the force exerted by the now fully-matured Ten-Tails as it escaped the hole it had seemingly been trapped in. Arriving to where Neji's corpse was, Guy tells a weeping Lee not to cry and that if they remembered Neji and his feelings, then he would live on inside them forever. This is later affirmed by Kakashi and Naruto, despite Obito's attempt to decry that sentiment. After receiving chakra from Naruto, Guy and the other shinobi charged towards the Ten-Tails. Launching Lee towards Madara, their combined effort was enough to sever the Uchiha's connection to the beast and forced them to retreat to the ground.

Later as he saw the Four Red Yang Formation erected around the Ten-Tails, Guy informed Lee that the technique was no easy feat and that only shinobi of Kage-calibre were able to erect such a powerful barrier reputed to be stronger than even the Four Violet Flames Formation. With the situation later turning grim as the Alliance was trapped in a barrier with a Tailed Beast Ball-firing tree, Guy and the other shinobi soon found themselves shrouded in the previous Version 1 mantles again. He and the other subsequently found themselves on the outside of the barrier, escaping the near-fatal attack thanks to Naruto and Minato's action.

Return of Madara Arc
True to his nature, Guy continued to push himself even after becoming too exhausted to stand on his own. With Lee supporting him, Guy and his students noticed Gaara speeding past them, Guy began to worry about the situation. As the team decided on their next move, Madara, having recently revived himself and became the Ten-Tails' jinchūriki, expelled the Benihisago and Kohaku no Jōhei, deeming the two legendary tools as useless, which comically land on top of Guy and Lee. Guy later saved Kakashi from Madara's attack, with Minato thanking him inwardly as Madara wondered when he had seen him before. Guy, on the other hand, didn't recognise him.

After being informed that the person before him was none other than Madara, and that only taijutsu or senjutsu could affect him, Guy wasted no time in opening the seventh gate and launching an assault on the Uchiha. Attacking him with his Daytime Tiger technique, the two were sent reeling from the impact with Madara wasting no time to counter-attack, sending one of the black orbs flying at Guy. He was ultimately saved by Rock Lee who appeared on the battlefield shortly after.

With the situation getting dire, Guy resolved to open the eighth gate to battle Madara, telling Kakashi that it was time that he became a crimson beast. Resolute, Guy is not dissuaded by his comrades. Comforting his protégé, Guy told Lee that it was not time for tears before dashing of to confront Madara once again. Inserting his thumb into his chest as he went, Guy opened the Eighth Gate. Reflecting on his life and ultimately that of his father Might Dai, he mused on how similar the situation was when his father had sacrificed his own life for him. Though Madara tried to trivialise Guy's sacrifice as nothing more than leaves falling and rotting in autumn, Guy declared that those same leaves would become nourishment for the new leaves that would grow. Upon reaching his target, Guy unleashed the "Gate of Death" and uses Evening Elephant.

Stopping after the initial attack as his body already began feeling the negative effects the eight gates, Guy quickly adjusted to the pain, and continued his assault, soon overwhelming the jinchūriki. Supporting his assault, Guy's allies quickly joined in and were able to deprive Madara of most of his Truth-Seeking Balls, allowing Guy to deliver the final blow of his attack. While visibly battered and winded from the assault, Madara soon returned to his feet, delighting in the experience and shocking Guy.

While continuing to gradually wear down Madara, Guy soon realised that he was not dealing enough damage to stop Madara in time. He then resolved to use his final technique — Night Guy. As delivered the final attack, obliterating the left side of Madara's torso, Guy finally succumbed to the Eighth Gate's after affects and collapsed. As Guy's life-force began to wane, and his body starting to turn to ash, a regenerating Madara decided to show Guy his final respect by finishing off the taijutsu master personally, only for his attack to be repelled by Naruto. With a newfound power, Naruto was able to stabilise Guy's life-force.

Naruto: Shippūden the Movie
He made a cameo with Kakashi when Konoha received an urgent message from the Land of Demons. Guy later joins Kakashi, Tenten, Iruka Umino, and Anko Mitarashi in launching a counterattack against Mōryō and his stone soldiers to buy time for Naruto, Neji, Sakura, and Lee, who were protecting Shion, to defeat Mōryō. He was later seen with Kakashi after the stone soldiers retreated.

Naruto Shippūden 4: The Lost Tower
A young Guy, along with Shizune, Asuma Sarutobi, and Kakashi Hatake, is seen waiting in a long line at the grand opening of the Ramen Ichiraku.

Naruto 5: Blood Prison
Guy is shown, with many other villagers in Konoha, in a flashback as Naruto is trying to enter Sage Mode.

Naruto 6: Road to Ninja
In the alternate world, Guy is a depressive, unenergetic, middle-aged shinobi who thinks of himself as an old man past his prime time.

Trivia

 * In the Shonen Jump magazine, Viz rendered Guy's name as "Mighty Guy" in some of the earlier chapters; this was changed back to "Maito Gai" in most of the graphic novel stories, and later changed to "Might Guy" when the guidebooks were released.
 * The name "Might Guy" is a joke aimed at the "hot-headed hero" archetype that appears in many movies and anime.
 * Guy's appearance and mannerisms seem to be based off those of Bruce Lee. He even wields nunchaku and wears a jumpsuit.
 * As of chapter 595, Guy has had all four of the compass point animals in Feng Shui associated with him: Morning Peacock being the Vermilion Bird, the Afternoon Tiger being the White Tiger, The Turtle as his summon and the Dragon being the basis of the design of his Nunchaku.
 * Studio Pierrot's Settei sheets of Guy show that he was 143cm in Naruto Shippūden 4: The Lost Tower.
 * According to the databook(s):
 * Guy's hobbies are repeated side-steps, and hitting focus mitts.
 * Guy wishes for a rematch with Kakashi.
 * Guy's favourite foods are super-spicy curry rice and curry udon, though he finds it impossible to dislike food.
 * Guy's favourite phrase is.
 * Guy has completed 788 official missions in total: 86 D-rank, 270 C-rank, 210 B-rank, 199 A-rank, 23 S-rank.
 * Strangely, even though aoi could mean green or blue, most current Viz subs and dubs refer to Guy as the "Blue Beast" rather than "Green Beast", though this is explained in the manga to correspond to the steam that surrounds him when he unleashes his Eight Gates power.
 * In Naruto: Ultimate Ninja Heroes, Guy calls himself "Beautiful Savage of the Leaf Village".

Quotes

 * (To Lee) "Yes!! This is what youth is all about!"
 * (To Lee) "It's true that you're different from Neji… You're not a genius in ninjutsu nor genjutsu, not even taijutsu… But you know what Lee? You are a genius that has the strength and potential within himself to surpass Neji… …Because you are… a genius of hard work."
 * (To Lee) "For those who don't believe in themselves… hard work is worthless!! …You are very much like me, Lee. I used to be a loser too. But these days I can even win against the elite genius Kakashi."I want to prove that even without ninjutsu and genjutsu I can become a great ninja" that's your nindo right? That's a great goal, it's worth working hard for!"
 * "No, now the tables will turn. The lotus of Konoha blooms twice!"
 * (To Kakashi) "What would you know about that boy? That kid has a precious thing he would give up his life to prove. So I wanted to turn him into a man that could accomplish it… That is all…"
 * (To Gaara after saving Lee) "He is my beloved comrade."
 * (To Lee) "You worked hard Lee, there's no doubt in my mind the surgery will be a success. You have the power to shape your own destiny. And on the one-in-one thousand, no, one in a million chance something to happen to go wrong, I will die right along with you. Since the day I met you, my nindō has been to train you to become the most splendid ninja possible. That's a promise!"
 * (About Kisame Hoshigaki) "Water Release ninjutsu… and that huge sword! You must be… …Someone I've met before!"
 * (About Kisame) "He was a worthy opponent! A man who lived and died like a real shinobi! Kisame Hoshigaki! I'll remember that name for the rest of my life!"
 * (To a Kumo-nin) "Your comrades will die on the battlefield! You have to be prepared for the worst! If you let it get to you, even more people will die! Turn one comrade's death into another's life! Got that rookie!?"
 * (To Kakashi) "Our youth isn't finished yet! Don't throw away hope! Indeed, it's not always possible to do what we wish to do… However, it's important to believe in something before you actually do it. That was my spirit when I challenged you."
 * (To Madara) "…That may be true… but they don't just rot and die!! They will become nourishment for the new, fresh leaves! The time when a new spring comes and the fresh leaves bud… is the peak of youth!! It's the time to burn, deep crimson!!!"