The gates of Tartarus in the Umbreal Plane.

Tartarus is the home demi-plane of the Empyrean Titan Azogun. Located in the Umbreal plane, Tartarus can be accessed by following the river Styx or via special pools of shadow connected to Styx on the material plane.

Tartarus is a massive prison containing thousands of imprisoned souls thought too dangerous or powerful to be allowed proper rest. It is also the resting place of the Titan Lyttas as well as other monstrosities that threaten Empyrean rule.

Tartarus is the place where the greatest sinners are sent. Bards describes it as a valley, surrounded by great dark rivers and walls to prevent sinners from escaping from it. It is guarded by an colossal hydra with fifty black gaping jaws, which sits at a screeching gate protected by columns of solid adamantine, so hard that nothing will cut through it. Inside, there is a castle with wide walls, and a tall iron citidel. Tisiphone, queen of Azogun's Erinyes stands guard sleepless at the top of this turret lashing her whip at the caged prisoners below. Far beneith the citidel, through the labyrythlike structure is Azoguns throne and his sister Lyttan's chained remains. Azogun himself gloats over his most prized captives, a list that includes some of the cosmos's most deadly beings, deemed a threat to titanic rule.