Stygis the Fearmonger

Stygis the Fearmonger, First Head of the Three-Headed Serpent and God of the Ophionic Empire
Stygis is a dead god, the most powerful of the triumvirate called the Three-Headed Serpent. She is a rarity, a divinity dedicated not to order, but to chaos, and the Ophionic Empires flourish in spite of her, rather than because of her. Her own priests, the Nightmare Speakers, are agents of pure chaos, whose only goal is to increase the flow of blood across their mistress's altars.
Her power, as the primary deity of an entire empire, is immense, but her own nature prevents her taking control of more of the Abyss. Not only is she unable to tolerate any kind of organisation, her many betrayals at the hands of her cohort Sythis have bred in her a habit of entrusting multiple lieutenants with often conflicting tasks so that none of them know enough to overthrow her. It is principally her paranoia, ably stoked by agents of Bleys Greyshade, that keeps her from overthrowing the Perilous Athenaeum and seizing control of Inveris.
Stygis has the form of a woman from the waist up, mounted on the body of a colossal serpent. Her human head is surrounded by the six serpentine heads of a Yuan-ti anathema. Once, she might have been divinely beautiful, but as a dead god her form is withered, her hair dry and colourless and the serpent scales dry and cracked, her flesh rotted and face sunken. Only the anathema heads possess a full measure of vitality, with vivid scales and bright eyes. She wears a coiled golden diadem on her human brow, an image of the serpent crown of the Ophionic Empire, and drapes her ruined form in elaborate finery.