Tartarus

Below the underworld. Below the roots of Olympus. Below even the deepest foundations of the earth - there is a place that has no other name.
TARTARUS tells the story of the deep itself: the primordial abyss that existed before the gods, that received the defeated Titans in their chains, that holds the condemned eternities of Sisyphus and Tantalus and Ixion and gives even the worst of them more than they expected. When Heracles descends further than any hero has gone, when the three judges bring the apparatus of justice to the darkest place in creation, when Chaos reaches down to speak with its own depth - Tartarus holds all of it.
Not as a prison. Not as punishment. But as what the deep has always been: the substrate of everything, the prior to everything, the thing that will remain when all arrangements return to what they came from.
An interior mythology of the abyss - told not from outside, looking down, but from inside, looking up at the world that sits on what it cannot see.
Before the gods. Before the earth. Before even the dark had a name for itself - there was the deep.
Tartarus is not a prison. It is the oldest place in existence, the substrate on which everything else is built, the permanence that outlasts every arrangement. The Titans are in it. The condemned are in it. The judges bring their fairness to its edge. Even Heracles, in his relentless descending, goes further than he was meant to go - and finds something looking back.
TARTARUS enters the abyss from the inside and discovers, in the deepest place anyone has ever written, something that is not cruelty and not indifference, but the weight of being the thing that holds everything else.