Lady of Pain
This enigmatic being serves as the ruler of Sigil. None know her origins, or even her nature; she has existed for as long as Sigil has, and Sigil has been known almost as long as mortals have existed on the planes. Never speaking and rarely intervening, she acts only through her servants, the dabus. Resembling the dabus in some respects, the Lady appears as an expressionless female, hovering a few inches above the ground, never making a sound. Her pale face is ringed by a crown of blades, protruding from her flesh.
There are almost as many theories about her origins as there are citizens of Sigil; some serious, others less so. Some claim she is merely a fiend, the first being to discover Sigil and thus taken by it to rule. Others claim she has her origins in the ancient past of the multiverse, a contemporary of the Serpent or the Dark Powers. Still others claim her a daughter of Poseidon, an advanced form of dabus, or even seven giant squirrels on each others shoulders with a ring of levitation and a costume.
The Lady has absolute power in Sigil; the portals of the Cage are fully under her control, and it is by her will that deities are unable to enter. Merely her shadow passing over a person will flay them alive, and she is known to have the power to cause other misfortunes as well. In the past, she dealt with those of the greatest risk to Sigil by imprisoning them in black crystals sent to the deepest layer of Pandemonium. However, she has since learned a more effective means of removing these individuals from her city. These folks, she now uses the Mazes to deal with. Those that would attempt to claim Sigil for their own, or otherwise move to act against the Lady, even those that merely choose to worship her are sent off into these constructs.
The Mazes are portions of Sigil itself, twisted around a person and cast off into the fog of the Ethereal as a new demiplane. These people, when least suspecting, will be traveling down an empty hallway or corridor, only to find a new twist they'd never noticed before. Down this path are more branching pathways, circling around on one another, intersecting continuously. Those trapped within a maze never age, and have no need for food or drink; for the rest of their lives, they have almost no fate to look forward to but traveling the Maze. As a further punishment, each maze contains somewhere hidden within it a single portal out, giving those trapped within the constant hope of escape, as unlikely a prospect as that is. Still, some few have managed to escape, and it is from these individuals that what little is known about the Mazes has been revealed.
Some say those pulled into Mazes leave trails behind, psychic paths much like the silver cords of Astral travelers; further, some believe such trails can be followed to lead a person to the Maze in which they have been trapped. A slight few, such as the hr'a'cknir Djhek'nlarr, have the ability to follow these trails and find entry into their Maze from outside. These individuals map out the Mazes they find, selling the portal keys and maps to other travelers. Such actions are heavy crimes in Sigil, however, and even mere possession of a map of one of the Mazes brings heavy punishment from the Harmonium, wishing as they do not to bring the Lady's wrath upon themselves by allowing this trafficking either explicitly or implicitly.