Hashirama Senju

, the, was the founder of Konoha, the older brother of the Second, and the grandfather of Tsunade, the Fifth Hokage of Konoha and Nawaki.

Backround
Hashirama was originally the leader of the Senju Clan of the Forest. At some point in his life he fought Kakuzu but the nature of this fight is unknown at this point. In his early years, after they and their clans had been fighting constantly, he had his clan allied with Madara Uchiha, and the two of them, with their clans, founded Konoha. Later on, he came to disagree with Madara over the policies of the village. This conflict resulted in the battle with, and defeat of, Madara Uchiha at the Valley of the End.

To commemorate the battle, two statues, of Madara and Hashirama, were carved into the earth around the waterfall. It is for this reason that Naruto Uzumaki and Sasuke Uchiha's fight at that location was noted to be ironic.

However the war still waged on, and unsure of the title of Hokage he would not only appoint his brother as his successor as the Second Hokage (Nidaime Hokage), but in a common decision with his brother they also decided that one of their students Sarutobi should become the Third Hokage (Sandaime Hokage), which in turn seemed like a wise decision as both brothers would eventually die during the wars.

Personality
He saw the people of Konoha as a part of his own family, and his legacy takes a firm root in the village. He was greatly respected by all and even Madara Uchiha had respect for his strength. Hashirama appears as a kind person, who can also joke around, even in the most serious situations.

Abilities
Hashirama Senju was famous for his jutsu, an ability to mix earth and water manipulated chakra to create the new element: wood. By converting chakra into life force, he was able to create actual trees. This ability also granted him power to control the tailed beasts bending them to his own will. It would seems the ability to controll Bijuu, is also greatly amplified by his necklace.

Konoha Invasion Arc
He and his brother is revived from the dead by Orochimaru using Impure World Resurrection to fight the Third Hokage during the invasion of Konoha arc. During this time he demonstrates his great Wood Release abilities and the same shows great Taijutsu skills. His soul is eventually sealed into the stomach of the Death God by the Third Hokage, along with his brother and Orochimaru's arms.

Part II
It is revealed that Orochimaru had implanted Hashirama's DNA into sixty test subjects in an attempt to gain access to his Mokuton techniques and ability to control tailed beasts, producing Tenzou (later given the code name Yamato). However, he lost track of the test subjects and didn't realize that one had survived.

Trivia

 * The Necklace worn by Tsunade and later won by Naruto originally belonged to Hashirama.
 * "Senju" (千樹) means "A Thousand Trees", fitting his ability to use Mokuton.