RoyalXIII

Aqua: Kind of a no-brainer. Kris and Aqua look like genetic siblings and her whole deal is that she's a carefree knife enthusiast who's less "Hmph…" and more "Mwehehehe >:3", perhaps alluding to Kris as a younger child.

Seth: Kris is often calling the shots during the Fun Gang's fights, thus Seth's tactician persona.

Green: There's the obvious angle of them not saying much, but I think the more interesting angle is how Green is supporting every side in the Flower World conflict to some degree, kind of like how Kris is, what, a double or triple agent at this point?

Yellow: Definitely has the most viscerally unpleasant implications of this bunch. If he reflects Kris, it's likely because of something having to do with the December incident, to say nothing of how the Chapter 5 Weird Route plays out.

Blue: Also reflects Kris's ambiguous allegiances. I'm struggling to think of more than that, but given Kris's skills with the piano, they could have a more artistic side that Blue plays off of.

Orange: Her immaturity and insistence that she's human despite looking more like a mouse also feels like a reflection of Kris's childhood as a horn-wearing human. Her insisting that she's being picked on at certain points might also point to a certain sense of alienation as a human in a monster-majority town.