Shannon

ottos mentor who is an part anglerfish tho no one knows what species or anything about the man as he is truely a mystery, he is a talented engineer but has done some stuff that others would call immoral (he has done things to otto in the past but yet otto still trusts him), Will not hesitate to expermient on other people.

was married to mitsuki before he went crazy one day(has always been a bit messed up tho is truely a pyschopath) and left her to care for their only child alone

While he is an evil scientist, he still needs money, so maybe he had government funding to "MAKE SEA REALM GREAT AGAIN" And it was right up his alley so he began with himself of course since he’s mad haha but he didn’t want to actually lose his life, so he kinda just experimented with some of his body parts. Maybe it didn’t start in his eye, maybe his arm or something (which is why he wears gloves and stuff in present day) At some point the corruption spreads more and up to his face and he says “screw it” so he takes out his eye before it can go further and kinda cuts off that body part (like circulation idk) and low key kills that side of his body then refuels it with blood so that it kinda reattaches.