I think he’s a prince of heart roleplaying a knight in imitation of Dave, just like Dirk, since…he’s a Dirk. He destroys Heart (forcing Dirk’s suicide in Unite Synchronize) to serve his Self to Jake (offering Jake Dirk’s head/his own self, encased in the glasses).

His roleplay may be intense/unhealthy enough that he echoes Mind (and/or maybe Time, during Unite Synchronize? since he does mention managing temporal logistics) but that doesn’t mean he’s not a Heart player.

And I don’t feel confident enough in my understanding of either Mind/Heart symbolism or of how, exactly, roleplay/Aspect shifting work to say for sure right now. Maybe Hiveswap will lead us to know more, but “Prince of Heart roleplaying Knight” is as specific as I’m willing to get.

I think AR’s existence as Scratch backs up that reading.
Knights’ serving of others gets them likened to Butlers, and Scratch is basically the best butler of all. Scratch easily parses as any combination of Prince/Knight and Light/Space, imbued as he is with First Guardian abilities and cueball omniscience.  And that’s before we take into account the other souls he’s linked to, of course–but still, AR’s Class predilections seem to be there.