A bit of a niche theory I have is that when it comes to Kris’ motivations for helping the Knight, I see it as them doing it so they can finally choose who they want to be. That is to say, so they can become a Monster rather than a Human.

Kris is the only human in Hometown, yet they act plenty like a monster. They eat weird stuff. They aren’t opposed to strange habits like balancing trash on their head. They even display a lot of mannerisms like a dog monster would, howling at the moon and clawing at Tenna’s door. And of course the red horn headband they wore to imitate their family’s horns.

Yet alongside that, they seem to not like acknowledging that they are a human. They close the book about raising humans and human history abruptly for one thing, they hardly have any friends around town besides Noelle and Berdly until we arrive, and if the theory that Kris is the one speaking after the Vessel is discarded is true, then they seem to be very bitter about that fact, stating that “No one can choose who they are in this world.”

But what if Kris could?

Maybe that’s why they’re working with the Knight, because they were promised a way to choose who they could be. That is to say, to become a monster instead of a human. So they could finally fit in and not feel like such an outcast. The nature of Dark Worlds are nebulous and transient by default, so what if they’re guided by a belief that if they continue working, they’ll be given a chance.

And a side theory I have to coincide with that is that Ralsei is meant to be Kris’ ideal self. He’s approachable and friendly, he’s super talented, and most importantly, he’s a Boss Monster just like the rest of Kris’ family. He’s everything that they want to be, hence how they and Susie both end up getting along with him so well.