Lamashtu

Lamashtu (pronounced lah-MAHSH-too) is the mother and patroness of many misshapen and malformed creatures that crawl, slither, or flap on, above, or below the surface of the World. Her unholy symbol is a three-eyed Jackal head, which may be represented in many ways, and her sacred animal is the jackal.
History
Lamashtu was once a mighty Demon lord who became the first such entity to achieve true godhood. In ages past, she was allied with Pazuzu a Demon lord, though the exact nature of their alliance is often disputed by scholars of demon lore. Some say they were lovers, others say siblings, or simply convenient allies. What is known for certain is that she lured the god Curchanus into her territory and beset him with swarms of demons and other monsters until he was weak enough for her to attack. By defeating him, she ripped his godly domain over beasts from him. This imbued the demoness with a small amount of his divine power.
Pazuzu was enraged by this shift in power, and as Lamashtu returned from that battle he betrayed and attacked her. He wounded her terribly, but her new-found divinity allowed her to survive; they have been dire enemies ever since. Lamashtu's vendetta against him is only equaled by Desna's own vendetta against her.
It is claimed by many monstrous humanoid races that she was their first progenitor and creator.