01: rattlesnake naga. i'm thinking this one because ko is a sort of half-zombie called a handead, and his bite can turn others into handead like him; it's also implied that his 'venom' is harvested for 'injections' so this can happen on a wide-spread basis. i make jokes about him unhinging his jaw and having no gag reflex and stuff but it's probably not really a joke.

admittedly i don't fuck much with naga or the skala-type scaley creatures so my ideas for ko are limited.

02: harpy. some kind of bird creature that appears angelic and glowing and draws someone in with kindness and love and also his mouth in order to kill them or something. thinking this one because of his godly nature; in his canon he's widely revered and worshipped as a god, and he leans into this. while i wouldn't want to make him quite so godly here, i'm thinking it'd be fun to have him kind of honeypot a victim and drag them in for sex or violence. not sure what he'll look like, really.

03: fucked up siren/koi monster. this one would be similar to the harpy but water-based, but he'd use his alluring voice which canonically can undo the brainwashing that affects the japanese population. again, not sure what he'd look like here so much but yeah.