Koyata? Don't read if you have not seen
--Spoiler--
After a sword through the side of his neck and a slice across the abdomen, he manages to live seemingly unscathed. Was he in fact "immortal" as Shinrouko asks of him (a spirit of the forest maybe) or was Koyata a manifestation of Shinrouko's mind? Maybe, possibly, a TylerDurden situation?