big buff burly baby, bbbb,,
the unwitting companion of Rui after his death, Cairos is not a wendigo, but a wechuge. He is unknowingly Athabaskan, and have broken many of their taboos without knowing--such as having a photo taken with a flash, listening to music made with a stretched string or hide (such as guitar music), or eating meat with fly eggs in it {unknowingly, at the time.} With the repeated breakage of their taboos, he grew into a twisted creature.
He became bonded to Rui due to the cave-in which took the latter's mortality. Afterwards, he followed Rui's trail to the morgue, where he followed his companion to his present house. Rui often visits Cairos in Ryuji's forested backyard, spending long amounts of time out there talking to the wechuge--despite not usually getting a response.
Cairos is a skilled huntsman, but honestly prefers fast-food and fatty foods than humans or wild animals. He's very gentle towards his friends, which he has very few of, but extremely protective them and violent to those he doesn't know.
His hands are scarred and extremely sensitive from an attempt on his life--he was forced close to a bonfire to make him melt, but they underestimated his strength and wild behavior and he broke free.