Centipede Kai angst is so funny to me because I'm gonna be totally real. I think Kai would forget he's inhuman. I think he was going through so much hell he didn't even clock something monstrous was happening to him. The others are the ones to notice he has like mandibles hiding between his cheek and teeth and Kai's only reaction is to squeal and yell GROSS for a few hours before he tries to do weird shit with it. It takes him a week and then he forgets about it.
He'll remember once in a blue moon and check to make sure the centipede-ness is still there, then go back to his daily business. His sister turned into a sea-dragon, his borderline brother has an oni form, one of his friends was a ghost for a while, 2 of them are robots, & the new sister he adopted does WAY more 'monstery' things than him on a regular basis. He has so many more things to worry about than the weird bug-scales on his back