Location from Kingdom of the Wicked by Kerri Maniscalco
The domain of the Crone — a realm older than Hell itself, where shadows have substance and the boundary between death and existence grows thin.
The Shadow Realm predates the Seven Circles and exists adjacent to them — a parallel domain that touches Hell, the mortal world, and something even older. Celestia rules here, and her realm reflects her nature: ancient, patient, and fundamentally unknowable. This is where the boundary between life and death grows thin enough to whisper across, and where powers that the demon princes consider mythical are simply part of the landscape. The Shadow Realm is not a place you visit — it's a place that allows you to exist within it, and the distinction is important. Nothing here happens without Celestia's awareness, and very little happens without her permission.
A realm of twilight and shifting shadows where light behaves as a liquid, pooling and flowing across surfaces that may be stone, may be void. The architecture — if it can be called that — seems to grow from the shadows themselves, forming and dissolving with the will of its ruler. Colors are muted to silver, charcoal, and deep violet. Nothing is fully solid; nothing is fully absent.
Also known as: Celestia's domain, the realm of shadows