[@Raijinslayer]
I dunno man, the only stuff we were given in the Canon is that gem fragments can posses stuff but it just makes them more aggressive over time. I feel like for Reggie to work, you just gotta throw stuff in. I would say that Reggie seems to be too fleshy, but then I remember Steven and Connie can fuse no problem. So I dunno how to help you there.