Magilla was a succubus that served Aeshama. She (in a disguise as his brother) and her thrall lured Valla away from her mentor to a bridge in the Shassar Sea but was defeated by Valla who threw her off the bridge and tied up her thrall before leaving.
Sometime later, Magilla (back in her disguise) tricked the hero(es) and Josen into helping her before ambushing them but was defeated and killed.[1]
In-game
Magilla appears in Diablo Immortal, in the elite quest "Stranger in the Sands."
Magilla has most of the common features of a succubus (pointed ears, wings, tail, clawed hands and hoofed feet). She shows no obvious horns in the game. Her wings have a golden hue. She wields a barbed whip as a weapon. In the game, her appearance is identical to the skin of a vile temptress