He is always a black color and was turned into this by a knife. One stab = You become something you truly believe in, It also counts what type of person you were. He always was blamed and never really made an impact even though he did things. He was like a shadow of other people. His belief was a kaiju. so shadow kaiju. a second stab from the knife equals death. The only way to become human again is if you kill the person who stabbed you with the same knife. and if you were killed by the knife (stabbed twice), You can awaken if someone else kills them with the knife. lol it looks like he denigrates while in a shadow even though he's not

Someone in the group has the knife. and is threatening him because he knows who it is.