Ereshkigal
Mythic, worshipped by the Akkadians of Sumer (modern-day Iraq), circa 2350–2150 B.C.E.
Ereshkigal, the older sister of Ishtar, was the Mesopotamian goddess who ruled Irkalla, the underworld. When Nergal, god of war and pestilence, visited Irkalla to bring food, he met Ereshkigal and they fell in love. He threatened to resurrect all of the dead if Anu did not allow them to marry and remain in Irkalla together. From then on, they ruled the underworld. Both are seen as dark and violent deities.