The Amaranthine City is widely seen as the heart of Mabar. Experienced planar travelers may find it familiar, for it’s a dark reflection of the Amaranthine City of Irian. Irian shows the city in its first days of glory: prosperous, clean, full of joy and life. The Amaranthine City of Mabar is a haunted shadow of this glory. Like its counterpart, this immense metropolis fills an entire layer, but here, its banners are faded and torn, walls are cracked, and fountains are dry. Shadows still move through the streets, a miserable reminder of the crowds that once filled the city. The rotting tapestries and chipped mosaics speak of a past age of wonders and glory. The two are unmistakably the same city, both in architectural style and the layout of its streets. This feels like the last days of a grand empire, an image of decaying grandeur; but there’s great power beneath the tragic façade. The walls may be cracked, but they are still mighty, and the mezzoloth’s rusty trident can kill you as easily as a polished one.
The city’s ruler, the Empress of Shadows, is the first and greatest of the Dark Powers. Her defining principle is hunger, the desire to consume all that is light, to expand her empire across eternity. She prefers an elegant fiendish form, with polished horns and chitin plates engraved with arcane sigils, but she can take the shape of any yugoloth. She spends much of her time presiding over the decaying pomp and grandeur of the Amaranthine City, but also closely monitors the campaigns in the Hinterlands and occasionally takes time to torment her hostages. The sages of Syrania believe that the Empress of Shadows chooses which fragments of other planes will be pulled into Mabar, and planar emissaries sometimes dwell in the Amaranthine City seeking to negotiate with her.
This city is the seat of the yugoloths; for every yugoloth in the Amaranthine City of Mabar, there is an angel in the city in Irian, all the way up to the Dawn Empress and the Empress of Shadows. Most likely, this is just a way of reflecting the planes’ core concepts—beginnings and endings, hope and despair. But it’s possible that Irian and Mabar are somehow the same—perhaps the Dawn Empress is the Empress of Shadows, and though they appear to exist at the same time, they reflect the beginning and end of the same spirit.
The layers tied to the Amaranthine City reflect its theme of imperial ambition and decaying power. Some embody desperation—a collapsing fortress awaiting an assault that will surely destroy it, or an abandoned sanitarium whose inmates are trapped and starving. These regions are inhabited by shadows, but the fiendish gardeners can instill near-sentience into them if it serves their purposes. Fragments claimed by the Empress of Shadows are drawn into her empire, and usually acquire a yugoloth outpost even as the life is drained from the region.