Entrance to Tartarus
Tartarus, in mythology, is the darkest and deepest area of Hades' realm, known as the Underworld, where the gods imprison their enemies, chiefly the Titans. Tartarus is also the primordial god of Nothingness, son of Chaos, and the father of the giants by Gaea. Kronos is known for being held there. When a monster is slain, it is sent to Tartarus until they reform, for a time ranging from weeks to centuries.