Mayfair "Role Aids" products: Favorites? Conversions?

[Evilhalfling]

I loved Lich Lords - the only one I ever got, but it you really had to base a campaign on it, and I was in the middle of another when I got it. I actually saw it in the used rack of the gaming store last week, and considered buying it again.

 

[DMH]

Question, what are the Denizens books? Are they strictly demons or do they cover anything that might be considered an outsider?