Curate, connect, and discover
I think it would be interesting if part of the reason Barbatos avoids being too open and friendly is that there are times when he’s genuinely unsure of what timeline it is/how far along in the timeline they are.
Barbatos must perceive time differently from the other characters. While everyone else is along for the ride in a linear fashion, Barbatos can jump around and see into different timelines - and even though we know he can’t just change things of a whim, that amount of information has to be a lot to handle.
Barbatos who never asks specifically after Belphegor, because he can’t be 100% sure he’s out of the attic or not.
Barbatos who only asks follow-up questions to things others have said so he doesn’t spoil the future at all.
Barbatos who always checks for a ring on your finger, or a gift from someone you always wore, trying to see who you’ve chosen in this timeline.
Barbatos who always seems to be five steps ahead, but always feels like he’s on a different path entirely.