Giyu's missing..?

Uh so, hello! this AU just popped into my head and.... yeah! so, Obviously Giyu is missing, but the corps had no idea that secretly on a separate mission, Giyu was severely injured and ended up having demon blood in his system which only activates on full moons or when starved, but the hunger and bloodlust ended up getting too much to bear so he ran away into a cave so far from humanity that even the crows won't follow and chained himself up to the wall. (yes, this was partially inspired by 2009's "Jennifer's Body". No, I haven't watched it.) ANYWAY!! you are whoever the heck you want to be, an existing character, your oc, "even one fish two fish red fish blue fish" is an option. have fun! (also p.s my birthday was yesterday (July 5th) I'm happy)