Lamashtu

Lamashtu was once a mighty demon lord who became the first such entity to achieve true godhood. In ages past, she was the lover of Pazuzu. 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, beginning an ancient vendetta with Curchanus’ protégée, Desna. 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.
When she learnt that demons were the result of experimentation by a Horseman of the Apocalypse, Lamashtu invaded Abaddon and killed the Horsemen Drulaema and Roshmolem. From torturing Roshmolem, Lamashtu learned the “art” of creating demons. Once she coupled that knowledge with the use of her own body to gestate the demons, she birthed the vavakia, a true masterpiece of the art of creating demons.
It is claimed by many monstrous humanoid races that she was their first progenitor and creator