Hashirama Senju

was a legendary ninja who hailed from the Senju clan that together with the Uchiha clan, established the first shinobi village: Konohagakure. He would later go on to become the village's.

Background
During Hashirama's time as the leader of the Senju, the clan came to be regarded as one of the two most powerful clans in the world, rivalling the renowned battle-oriented Uchiha clan. Because of this, when someone hired the Senju clan, the opposing side would hire the Uchiha clan and vice-versa, causing frequent battles between the two.

Eventually growing tired of the constant fighting, Hashirama and his clan approached the Uchiha and offered a truce with them. Allied with Madara Uchiha and his clan, the two groups founded Konohagakure. When deciding who should become the leader of Konoha, the villagers selected Hashirama over Madara for the title of First Hokage.

Fearing that Hashirama would oppress the Uchiha, Madara left the village, and challenged Hashirama's rule. After an intense battle that included the Nine-Tailed Demon Fox, Kurama, Hashirama defeated Madara; and Hashirama's wife Mito became Kurama's first jinchūriki by sealing the beast within herself. In the aftermath of their battle, Madara was believed to have been killed, and the resulting battle created what would come to be known as the "Valley of the End". To commemorate the battle, two statues, one of Madara and the other of Hashirama, were carved into the borders of the valley.

During his time as Hokage, Hashirama came into possession of a scroll filled with, among other skills, various kinjutsu, which he sealed away in order to keep the techniques within it a secret. He also defeated Kakuzu, who had been sent to assassinate him by Takigakure. At some point, Hashirama gained control of several tailed beasts. He spread these beasts to other, newly-formed villages in an attempt to maintain peace and equalise the powers between the nations. Thinking about the future of Konoha, he and his younger brother, Tobirama Senju, trained the young Hiruzen Sarutobi. Hashirama died shortly after the founding of Konoha in one of the many wars that were raging during this revolutionary era, but not before passing on the title of Hokage to Tobirama.

Personality
Hashirama was shown to be a very calm and collected person, as well as kind and caring, with a deep sense of loyalty, great charisma and negotiation skill. He saw the people of Konoha as a part of his own family, and his legacy took a firm root in the village. He was also shown to be a very wise and insightful man, as he passed on great teachings to Hiruzen. It was he who first believed that all Konoha shinobi should show true loyalty to each other, and that a Kage must be willing to put his life on the line for his village to set an example for all others. This belief of his is known as the "Will of Fire". Hashirama also seemed to have a sense of honour regarding his opponents and, despite their rivalry, possessed great respect for Madara Uchiha.

Appearance
Hashirama was a tall man with tanned skin, dark eyes and waist-length black hair typically styled in a centre-parted fringe that framed his face, although sometimes he wore it combed-back with two single locks framing his face instead. In most cases, his attire took the form of the standard shinobi dress of his era, consisting of dark red traditional armour — similar to that of samurai — worn over a simple black suit. This armour was constructed from numerous metal plates, formed into multiple protective guards along his body, in particular: chest, shoulders, thighs and forearms. Each collar of his shoulder guards bore the Senju symbol emblazoned on them. This clothing was accompanied by sandals and his village's forehead protector, after its formation. He often time also carried either a single large scroll strapped to his back or several large ones into battle.

While in the village, Hashirama tended to wear the traditional Kage attire consisting of the customary hat and haori over a full-length gown, along with a simple red headband. Otherwise, he wore a light-brown, short-sleeved, kimono shirt with mesh armour underneath, held closed by a red sash, and navy blue pants.

Abilities
Hashirama is reputed as the most powerful shinobi of his era, having been called the strongest shinobi even by his enemy Madara Uchiha. His strength was so greatly respected by the shinobi world that Madara himself claimed Hashirama was the one person whom they most admired and detested. Kabuto claimed that Hashirama's might was so vast, there aren't any living shinobi in the current era that could match his level of power. It was such that many considered his prowess to be a mere fairy tale much like the existence of the Sage of the Six Paths. The most common example was his ability to not only fight on equal footing with Madara despite his power of the Eternal Mangekyō Sharingan and control over Kurama but even gained victory in and survived the battle. As a further testament of Hashirama's prowess, Madara mentioned that fighting all five of the current Kage was trivial compared to his battle with Hashirama, and that with only one of them alive, the landscape would not change as drastically — a reference to the battle that created an entire valley.

As the leader of the Senju clan, Hashirama held tremendous proficiency in many shinobi skills and possessed a considerable understanding of those he did not. He held advanced ability in taijutsu with prodigious speed and strength. In addition, he was well-versed in genjutsu and could perform powerful illusions such as the Bringer-of-Darkness Technique. In the anime he showed proficiency with both kenjutsu and fūinjutsu, carrying a scroll which he used to store a number of large swords for the former and in the latter, his use of the Contract Seal to break Madara's control over Kurama.

Medical Ninjutsu
According to Madara, Hashirama was also able to use medical ninjutsu. His skill with which were such that he could heal himself without forming seals, and from the medical ninjutsu that his descendant Tsunade — who is considered to be the greatest medical-nin in the world as it is — has displayed, Madara surmised that his medical techniques were also on an entirely different level. The fact that he could use medical ninjutsu demonstrates that Hashirama likely had excellent chakra control.

Nature Transformation
He was most famous for his unique Wood Release techniques, a kekkei genkai that is a mixture of earth and water-natured chakra that creates this new element. By converting chakra into the source of life, he was able to create trees, causing them to grow to great sizes and manipulate them to diverse shapes and battle uses at will. It was said that this ability was used to create the very landscape and foundation that Konoha is built upon. This ability appeared to be exclusively his, as no other known member of his clan has ever displayed its use. Even those who obtained this power through unorthodox means, such as Yamato, stated that his use of Wood Release was much weaker in terms of raw power. He could create clones of himself, massive forests, or create gigantic flowering trees which were able to put targets to sleep. In an instant, he could shape the entire battlefield for his own uses.

Along with his kekkei genkai, Orochimaru also coveted Hashirama's unique ability to control tailed beasts. Of all his considerable talents, it was this ability in particular that made Hashirama unparalleled in the shinobi world, so much so that he is regarded as one of the few people capable of completely controlling a tailed beast. At one time, he had many of the beasts in his possession. This ability was greatly amplified by his crystal necklace, which Yamato suggested that he required to control even Naruto's partial lapses into tailed forms.

Invasion of Konoha Arc
Both he and Tobirama were reincarnated by Orochimaru using the Impure World Reincarnation technique to fight Hiruzen during the invasion. While fully aware of what was going on, and saddened that he would have to fight his former student, Hashirama and his brother were robbed of their free will as a result of a seal employed by Orochimaru into the back of their heads. Hiruzen quickly resolved to kill his masters and used a very powerful fire technique that was easily countered by one of Tobirama's walls of water that was then turned into an attack that was stopped by Hiruzen's own earth wall.

During the battle, he demonstrated great teamwork and combination attacks with his brother. He also demonstrated his great Wood Release abilities, forcing Hiruzen to summon Enma for assistance, and at the same time showed great taijutsu skills. His soul, along with his brother's, was eventually sealed by Hiruzen when he combined the Dead Demon Consuming Seal and the Shadow Clone Technique to strike both of them at the same time. Before his soul was completely removed, he and his brother apologised to their former student for the trouble they had caused.

Legacy
Because of the heritage of the Senju — who are direct descendants of the Sage of the Six Paths — and the kekkei genkai that he possessed, Hashirama's DNA is highly coveted. During the battle at the Valley of the End where Madara Uchiha was thought to have died, the latter took the opportunity to collect his adversary's DNA, using it to create a mindless living clone that produced the artificial life forms that became the White Zetsu Army, White Zetsu, and Spiral Zetsu. When he was reincarnated by Kabuto, Madara revealed that he can use the Wood Release kekkei genkai as Hashirama's DNA was integrated inside him.

Orochimaru, desiring Hashirama's unique abilities, exhumed the First Hokage's body for his own experiments where he infused sixty child test subjects with DNA harvested from his remains, hoping that one would prove able to use Wood Release. Only Yamato survived the process. This act also provided Orochimaru with a genetic sample that he used to reincarnate Hashirama years later, before Hiruzen sealed his mentor's soul away.

Danzō Shimura, using a similar experiment to Orochimaru's, infused his right arm with Hashirama's DNA, and then had ten Sharingan embedded on it. This synthesis not only allowed Danzō to access Wood Release, but also use Izanagi for extended periods and regenerate the Kotoamatsukami within a relatively short span of time compared to the decade it would've normally take. Obito Uchiha, having been saved by Madara, was indirectly infused with Hashirama's DNA when the destroyed portion of the young Uchiha's body was replaced with artificial material from the living clone of Hashirama. Taking over for Madara, with the aid of the Akatsuki, Obito used the tailed beast chakra sealed within the Demonic Statue of the Outer Path as well as the DNA of Yamato who was later captured, to enhance the White Zetsu army prior to the start of the Fourth Shinobi World War.

But the most positive aspect of the legacy that Hashirama left behind is an ideal known as the Will of Fire, a belief held by most residents of Konohagakure. Through sharing Madara's disdain for him, Obito — while under the guise of Madara — admitted that he has a begrudging respect and admiration for Hashirama and saw Naruto Uzumaki as the heir to Hashirama's ideology while proclaiming that Sasuke Uchiha inherited their clan's hatred.

Trivia

 * is a Japanese word referring to the space between two pillars. This might be a play on the word, as the Hokage is said to be the pillar that supports the village. '柱' is also the counter word for gods and buddhas.
 * His face on the Hokage Monument has a crack across the bridge of the nose. However, in flashbacks, no such scar is visible. This may be due to simple damage as Hiruzen's face on the monument suffered similar damage.
 * In the English dub version of the anime, his Wood Release was called "Secret Earth Jutsu" rather than "Wood Style". This was corrected in Shippūden with Yamato.
 * Hashirama, along with Tobirama, Minato, and the Konoha symbol, had his face appear in the ending omake of Shippūden episode 129 within the fireworks.
 * In the chapter 238 a portrait of Hashirama and the other Hokage is seen, showing him using a kerchief.
 * According to the databook(s):
 * His hobbies were bonsai and wood sculpting.
 * His desired opponent was Madara Uchiha.
 * His favourite food was mushroom mixed soup.
 * His favourite phrases were  and . They refer to perfect beauty without any artificial elements.

Quotes

 * (To Hiruzen) "The fellow countrymen of the Konoha make up each part of my body… those of the village believe in me, and I believe in them. That's what it means to be Hokage!"
 * "Whenever you live, there will always be war."
 * (As quoted by Kakashi) "Those who stray from the path of justice have no courage, but under the wing of a strong leader, cowardice cannot survive."
 * (To Kurama) "Nine-Tails, your power is too great. I cannot let you roam free any longer!"