[quote=@HeySeuss]Well, vampires and the such are naturally allies. Ghosts? I think Nemsemet, as a powerful necromancer, is enslaving them.[/quote]

That would make a lot of sense (and provide extra motivation for Beth, as it happens). He could also be recruiting, either by enslavement or summoning, creatures such as hellhounds, leviathans, reapers, banshees. I can see shapeshifters possibly siding with Nemsemet.