Spellcasters get to summon djinn, efreeti and elementals, which are all cool.
But if I want to keep my campaign Auran Empire-compatible, what are some more horrific and diabolic flunkies my evil sorcerers can summon from the veil between worlds?
I was thinking along the lines of AD&D demons and devils, and/or Mythos critters.
Demons do exist in the Auran Empire. They are native to the Chthonic Darkness, also sometimes known as the Abyss and the Outer Darkness
I have used both Mythos creatures and creatures from the AD&D 1e Monster Manual. The Balor, Marilith, and Hezrou have all appeared in Auran Empire campaigns.
Mayfair Games did a bunch of infernal denizens in the Demons and Demons II boxed sets, plus the four “Denizens” monstrous compendiums: Denizens of Diannor, Denizens of Og, Denizens of Vecheron, and Denizens of Verekna. They were designed to be compatible with AD&D, but I have three of the Denizens sets, and they’d convert pretty easily.
I haven’t seen PDFs available for sale. The online stores for Paizo and Noble Knight both list some of the line, but it looks like it’s all hard copy for both stores.