Shodaime Hokage

The First Hokage (火影初代, Shodaime Hokage; Literally meaning "First or Founding Fire Shadow") was the founder of Konoha, the older brother of the Second, and the grandfather of Tsunade, the Fifth Hokage of Konoha. His surname is Senju, while his given name is unknown. The First was famous for his Mokuton (木製解放, Wood Release) 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 Bijuu, bending them to his own will. 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 originally the leader of the Senju clan of the Forest. At some point in the First's life he fought Kakuzu but the nature of this fight is unknown at this point. In his early years, he allied with Madara Uchiha, and the two of them 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.

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

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

Life
The first Hokage of the Hidden Leaf Village is extremely strong. Shodai, and his brother Nidaime (the 2nd Hokage) trained the current Hokage, Sarutobi (the 3rd) to what he is today... though they both died early in their leadership leaving Sarutobi to train himself.

One of the Jutsus that only Shodai knows is Forest Genesis, where he feeds his chakra to the surrounding plant life making them large and strong and to trap his opponents.

When Orochimaru resurrects Shodai in Zaku's body, he is forced to battle his student, Sarutobi. Sarutobi manages to place a seal on him which traps the soul in the "belly of death" where there's no escape... however Sarutobi dies as well.