Ashmadai

The Ashmadai, or the Messengers of the Raging Fiend, were a secretive devil worshiping cult dedicated to the god Asmodeus, based in Neverwinter in the late years of the 15th century DR. See: https://forgottenrealms.fandom.com/wiki/Ashmadai

Aurelien says they're a real threat if they found a network. King of the Nine Hells.