Tobirama Senju

The is the younger brother to the First Hokage and Tsunade's great-uncle. As the brother of the First, the Second Hokage was a member of the Senju Clan of the forest.

Background
The Second Hokage is the brother of the First Hokage Hashirama Senju, and part of the Senju Clan. Eighty years prior to the current time line, the world was in a time of war and the ninja clans was nothing more but assassins for hire for the various feudal lords. Because of his brother, was the Senju clan constantly being hired for wars and in turn would the enemy then hire the Uchiha Clan. However the Senju would soon find it meaningless to continue fighting and offered the Uchiha Clan a truce, something Madara Uchiha was not verry happy about, but did agree.

Eventually, would the allied Senju Clan and Uchiha Clan, make a pact the feudal lord of the Land of Fire and the Second Hokage would together with his brother and Madara Uchiha foster the village Konohagakure, and helped create the "one village per country" rule that would eventually end most of the wars between the feudal lords. However there were still internal fights and after the fight between Madara and Hashirama the village soon began suspecting the Uchiha Clan of treason, and plotting against the village.

During this time would the Second Hokage also train a three man team of his own, called Team Senju consisting of Sarutobi, the future Third Hokage, and the two future elder advisers of the village.

However the war still vaged on, and unsure of the tittle of Hokage, would Hashirama appoint his brother as the Second Hokage and later would the Second also appoint his student, Sarutobi to be the Third Hokage.

After becoming the Hokage, would the Second give the Uchiha Clan a special position as a sign of trust. He gave them the leadership of the Konoha Military Police, however this was just a coverup, and its true purpose was just to distance the Uchiha from the government of the village, and the clan under a tight surveilance, with the ANBU Root.

Abilities
He was hailed for being the greatest master of water jutsu, being able to create water from nothing, allowing him to use any Suiton jutsu without requiring a source. However it could be speculated that he is just gathering the water vapor in the air to gather large amounts of water, for his all powerful jutsu. Also for his Water Release: Water Dragon Blast Technique that usually requires the largest amount of handseals, he is only seen using two handseals to activate and use it.

Destruction of Konoha arc
He is later revived from the dead by Orochimaru using Impure World Resurrection to fight the Third Hokage during the Destruction of Konoha arc. His soul is eventually sealed into the stomach of the Death God, along with his brother and Orochimaru's arms.