Lord Zack's Planescape
Hades is the layer of the plane that is often referred to by the same name that is home to the power of the same name. (Confused yet, berk?). The layer is sometimes called Pluton to distinguish it. The Underworld is the divine realm of Hades, the Olympian power. It is underground and the gate is guarded by Cerberus, a three-headed dog of exceeding power. The tunnel to the Underworld connects to the base of Mount Olympus and to all Material Planes the Olympians are worshiped.