The Hidden protector.

More about Takam Dammar the Hidden Protector. He is not human but an ancient forest spirit. A human "hippie" came into his forest and this ancient forest spirit attacked and killed the human thinking he was like all humans evil. As he killed him he glimpsed his soul and realized the hippie was trying to live harmonsly within nature. The forest spirit felt an overwhelming sense of guilt and at the same time curiosity about the humans he possed the hippie and has been both trying to learn and repent for the mistake he made.

Takam can meld with trees and other forest things to use as armor or basically use a tree as a walking mech suit to smash enemies. He also communicates with all manner of life. No one knows his secret but Sage and Eideard suspect something.