Hera

"None dared approach the queen of the gods, a reputation she cultivated."

- Lore

Hera, in ancient Greek religion, is a daughter of the Titans Cronus and Rhea, sister-wife of Zeus, and queen of the Olympian gods. The Romans identified her with their own Juno. Hera was worshipped throughout the Greek world and played an important part in Greek literature, appearing most frequently as the jealous and rancorous wife of Zeus and pursuing with vindictive hatred the heroines who were beloved by him. From early times Hera was believed to be the sole lawful wife of Zeus; she soon superseded Dione, who shared with him his ancient oracle at Dodona in Epirus.

Hades
Though Hera does not physically appear in the game, she is mentioned as being the previous wielder of the Heart-Seeking Bow during the Titan War and was greatly feared by all for her deadly accuracy. At some point, presumably after she married Zeus, she would discard her weapon as she had other more important things to focus on.

Additional notes
For additional information on Hera that does not pertain to Hades, see Wikipedia's article: Hera