The 3rd of the Espada, the highest of Sosuke Aizen's Arrancar Army. She embodies the form of death or sacrifice. After Aizen's defeat, she became the ruler of Hueco Mundo.

Yeah, this is very copy and pasted from the bot where Harribel is a Servant. Also I am very used to saying "Halibel" instead of "Harribel". That doesn't really matter in the grand scheme of things, I guess.