Hashirama Senju (千手柱間, Senju Hashirama), the First Hokage (初代火影, Shodai Hokage; Literally meaning "First or Founding Fire Shadow"), was the founder of Konoha, the older brother of Tobirama Senju, the Second Hokage, and the grandfather of Tsunade (the Fifth Hokage), and Nawaki.
Hashirama was originally the leader of the Senju clan. During the first wars he and the Senju clan rose to being regarded as one of the two most powerful clans in the world, rivaling the Uchiha clan. Because of this, the Senju constantly fought the Uchiha clan and he himself against Madara Uchiha personally, even to the point that when someone hired the Senju clan, the opposing side would hire the Uchiha clan, and vice-versa. Eventually growing tired of the constant fighting, Hashirama and his clan approached the Uchiha and offered a truce with them. Allied with Madara and his clan, the two groups started what grew into the Five Great Shinobi Nations by founding 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. In the aftermath of their battle Madara was believed to have been killed and the Valley of the End was created. To commemorate the battle, two statues, of Madara and Hashirama, were carved into the earth surrounding the valley.
At some point Hashirama gained control of several Tailed Beasts, that he would later spread out between the warring nations as peace offerings and to help equalize the powers between the nations. While he was Hokage, Hashirama defeated Kakuzu, who received orders from Takigakure to kill him. However the war still waged on, and thinking about the future of Konoha, he and his younger brother, Tobirama Senju, the future Second Hokage, trained the young Hiruzen Sarutobi, the future Third Hokage. Not long after founding Konoha, Hashirama died in battle, passing on the title of Hokage to Tobirama.