Tobirama Senju

, the, was the younger brother of the Hashirama Senju (the First Hokage) and the granduncle of Tsunade (the Fifth Hokage) and Nawaki.

Background
Tobirama was a member of the Senju clan along with his leader and brother the First Hokage, Hashirama. When, decades before the start of the series, Hashirama struck a peace treaty with Madara Uchiha, Tobirama helped them to found Konoha. When the First died, Tobirama was appointed as the Second Hokage. He was responsible for establishing Konoha's organizational system by setting up various organizations, such as the Academy, the ANBU, the chūnin exams and the Konoha Military Police Force 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 under the ANBU.

Tobirama 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 Great Shinobi World War that 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. Having realized that the only way any of them could escape alive was for one of them to sacrifice themself as a decoy and having faith that he had trained his students well to be the future of their village, Tobirama chose to sacrifice himself, but not before he selected his prized student Hiruzen, for the position of Third Hokage. Homura and Koharu would become Hiruzen's advisors. After giving the title of Hokage to Hiruzen, Tobirama went off to fight the enemies where he died a noble death in battle.

Personality
From what has been seen of Tobirama, he had pride in his abilities involving water jutsu. He also had a sense of humor, 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.

Appearance
Tobirama was a tall shinobi characterized by his red eyes and his red streaks under his eyes and on his chin. He wore a blue armor similar to his older brother with the addition of white furry tufts around the back of the neck and a forehead protector somewhat similar to Yamato's which also hung down to frame both sides of his face.

Water Release
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. He could manipulate it to form projectiles or tentacles, and could even perform the Water Release: Water Dragon Bullet Technique with only one hand seal (use of the jutsu normally requiring 44 hand seals).

Swordsmanship & 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 older 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 to rob Tobirama of his free will. His soul was eventually sealed by Hiruzen with the Dead Demon Consuming Seal, along with his brother and Orochimaru's arms. Before his soul was completely removed, he and his brother apologized to their former student for the trouble they had caused.

Trivia

 * Tobirama is the brother of the First Hokage, trained the Third Hokage, and is the granduncle of the Fifth Hokage.
 * Tobirama is known as the greatest water manipulator that ever existed.
 * Tobirama is a playable character in the Naruto: Ultimate Ninja series and in Shinobi Retsuden III
 * Tobirama, along with Hashirama, Minato and the leaf village symbol, had his face appear in the ending omake of Shippūden episode 129 within the fireworks.

Quotes

 * "''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."