Aha, your first sentence reads like a list of my fic kinks. Glad they're shared by someone else! My first thought on reading 'evil ex,' though, was Scott Pilgrim. I, uh, really hope the Doctor doesn't have five more of the damn things because, as fun as they are to write, there's no room for them.

Let's be honest here - the War Chief is a fairly unreliable narrator as regards Koschei and Theta. But I definitely see Theta as the more social out of the two, so maybe there's some truth to it.