While Tsunade traveling around the Land of Fire she found a baby in one of Orochimaru's laboratory, and she learns that he was created from her grandfather cells to be his clone.

The baby had the same tanned skin and dark eyes as Hashirama, and the only difference is that he has a dark green hair instead of black.

Tsunade who no longer able to give birth, nor she wants, decides to adopt the child and take him as her son, giving him the name of Senju Hashira.

What Tsunade doesn't know is that Hashira also has the DNA of White Zetsu that Orochimaru stole when he was in the Akatsuki, so he has small part of the Shinju power, and because of this he has the ability to become a Shinju in a human form if he ever takes some of the chakra of all of the tailed beasts, making him has the potential to be the world savior or destroyer.

Some of Hashira's abilities:

1- Massive reserves of strong chakra.

2- Powerful life-force that grants him an extreme longevity, regenerative power, stamina, and vitality.

3- Mokuton

4- Sensor

5- Kagerō: Like White Zetsu he is able to merge his body with the ground and flora and travel at very high speed, also once merged his presence is completely concealed.