Who~a, an honest to god vampire! [ well there are jiangshi (or at least one) in teyvat so let's just assume he knows what vamps are. why not. ] They sounds like quite the distinguished doctor. Must really know their way around hematology I imagine...

Would they happen to have thrall? If so or not, I'm certain they must be charming. What might they do, I wonder, if someone considerably more mortal would confess to them?