Greek Mythology
In Greek Mythology, Hera is the queen of Mount Olympus. She is the wife of Zeus, and also one of the original six Olympian siblings. This also makes her the sister of Zeus as well, along with being the sister of Poseidon, Demeter, Hestia, and Hades.
God of War
Hera is mentioned in the first God of War as a part of puzzle, where the player has to locate the "Hera's Necklace". She is the wife of Zeus, but never appeared in any other form in a God of War media to date. Hera will probably make an appearance in God of War III, most likely as a boss, since she has a voice actress next to her name on IMDb.