Slayer

Slayer is an artificially created spirit that is very chaotic and a lot of the times an asshole. He also traumatized Shy, however that wasn't really a choice? The guy who created him basically kidnapped Shy after he died (so Xiuhcoatl wasnt supposed to go to hell, but this demon wanted his body for experiments and decided to just take it) and implanted Slayer in there even though Shy's soul was also in there. Think the Host. Anyway eventually Slayer did feel sympathy (took him a while to gain that), and finally did Science and got his own body. He was still an asshole though. He worked as a mercenery for a while too.

Slayer is bi, and he's actually genderfluid (physically too bc he thought that if he has magic he may as well put it to good use) but people forget that a lot. He's not the best person to be in a relationship with, mostly because he's actually really insecure about the whole "im still learning how to function as an actual person with emotions", but he dates every now and then for the thrill of it.

Slayer doesn't exactly hate Shy, actually he feels responsible for him, but since Shy hates him he usually keeps his distance. For Solitude, he feels a sort of familial bond, but he has no idea why. (Its because they met a really long time ago but its not like you remember every person you put a sword through haha). Slayer thinks Robbie is cute in a "I want to ruin him" kind of way, so he lowkey teases him all the time to see his reaction. I think he actually falls in love with him eventually though, which is scary (to him at least).