Tobirama Senju

was the. He hails from the Senju clan, who along with the Uchiha clan, founded Konohagakure.

Background
Tobirama was a member of the Senju clan along with his leader and brother Hashirama. Decades before the start of the series, Hashirama struck a peace treaty with Madara Uchiha, Tobirama helped them create Konoha. When Hashirama, the First Hokage, died, Tobirama was appointed as the Second Hokage. During his reign he was primarily responsible for establishing Konoha's organisational system. He did this by setting up various organisations such as the Academy, the ANBU, the Chūnin Exams and the Konoha Military Police Force, the latter of which he created as a sign of trust towards the Uchiha clan. However, according to Madara, the Military Police was actually established to distance the Uchiha from the government of the village and place the clan under a tight surveillance by the ANBU. During his tenure, he and the Second Raikage met to form a formal alliance between Kumogakure and Konohagakure, however, Kinkaku and Ginkaku, Kumo's Gold and Silver Brothers attempted a coup d’état against the Second Raikage and left Tobirama near death in their surprise attack.

He also trained a three-man team of his own, Team Tobirama, which consisted of Hiruzen Sarutobi, Homura Mitokado, and Koharu Utatane. During a mission in the First Shinobi World War, on which Team Tobirama performed with Danzō Shimura, Kagami Uchiha and Torifu Akimichi, they found themselves surrounded by twenty elite Cloud ninja, known as the Kinkaku Force. Tobirama then realized that the only way any of them could escape alive was for one of them to be a decoy and sacrifice themselves; therefore having faith that he had trained his students well, he chose to sacrifice himself after he selected his prized student Hiruzen for the position of Third Hokage. Homura and Koharu would later become Hiruzen's advisers. After giving the title of Hokage to Hiruzen, Tobirama went off to fight the enemies where he died a noble death.

Personality
From what has been seen of Tobirama, he had pride in his abilities involving water jutsu. He also had a sense of humour, even under stressful situations. Like his brother, Tobirama felt a great deal of loyalty to the village, and placed its well-being above his own. Tobirama was strong-spirited, and passionate.

Appearance
Tobirama was characterized by his blue armour, white shaggy hair, red eyes and his red streaks under his eyes and on his chin. His forehead protector resembles a face guard similar to Yamato's. Underneath his armour, his outfit had a white fur collar and simple shinobi sandals. Outside of his shinobi outfit Tobirama has been seen in a simple blue shirt kimono held closed by a pale yellow sash and pants with mesh underneath, completed with a hand guard of sorts with what seemed to be a bracelet.

Abilities
According to a young Danzō, Tobirama was the most powerful shinobi in Konoha during his time. Tobirama was also the creator of the Summoning: Impure World Resurrection technique; however, shortly after its creation he labelled it as a Kinjutsu and never mastered it himself. Also, by simply touching the ground with his index finger, Tobirama could detect the presence and number of enemy shinobi. According to the Fourth Hokage, Tobirama was also very skilled in space–time ninjutsu.

Nature Transformation
Tobirama was primarily known for his mastery of Water Release jutsu, being able to make use of powerful water-style jutsu in areas where there were no bodies of water, making him known to be the greatest water manipulator that ever existed. He could manipulate it to form projectiles or tentacles, and could even perform the most complex of water-style techniques with only one hand seal.

Swordsmanship and Physical Ability
In the anime, it was said that he wielded the Sword of the Thunder God, a blade with electrical abilities, and was said to have mastered its use despite the lethality. He is also shown to have great physical prowess and a considerable amount of skill in the area of taijutsu, as well as good teamwork with his elder brother, Hashirama Senju.

Invasion of Konoha Arc
Both he and Hashirama were revived from the dead by Orochimaru, using Impure World Resurrection, to fight Hiruzen during the invasion of Konoha. While fully aware of what was going on, and saddened that he would have to fight his former student, Orochimaru employed a special seal into the back of their heads to rob Tobirama and his brother of their free will. 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, forcing Hiruzen to summon Enma for assistance. Hiruzen was however in his old age unable to defeat the two Hokage, as any damage that was done was simply regenerated and was further inhibited by his desire to not hurt either. 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 apologized to their former student for the trouble they had caused.

Legacy
Tobirama's legacy in the Ninja World at large is mixed. He was known for revolutionizing the ninja system by establishing organisations such as the Academy, ANBU, and giving the Uchiha Clan the Konoha Military Police Force as a sign of trust. He also passed on his Will of Fire to the next generation.

He was also responsible for the creation of Summoning: Impure World Resurrection technique, which has been used by the enemies of Konoha: Orochimaru who used the technique to battle his teacher Hiruzen, and Kabuto Yakushi who used it to wage war on the Five Great Shinobi Countries, on behalf of Akatsuki.

Trivia

 * Tobirama is a playable character in the Naruto: Ultimate Ninja series and in Shinobi Retsuden III.
 * Tobirama, along with Hashirama, Minato, and the Konoha symbol, had his face appear in the ending omake of Shippūden episode 129 within the fireworks.
 * According to the Naruto Databook:
 * His favourite words were.

Quotes

 * (To Hiruzen) "Do you hear? Guide the people, and believe in them, for it's from among them that one will come who will carry on when your time is done."
 * (To Hiruzen) "Saru, you must protect those who have faith in you and who love the village, and train up to those to whom you can entrust the next generation... tomorrow, you will be... Hokage...!"