Sigil

Place

Sigil is a unique city in the center of the Outer Planes. It's nicknames include "the City of Doors" and "the Cage." These are both references to many portals within the city, and the fact that portals were the only way in or out of Sigil, until recently.

Dabus' Blessing

The Dabus' Blessing is always in effect anywhere on or around Sigil. If one being intends to communicate with another, they are automatically understood. The Blessing partly explains Sigil's extraordinary success as a trade hub.

Environment

Incidentally, the tears in the ground the Hoarder emerged from and plowed open reveal a hodge-podge of dirt, old stone, something like iron cables, something like lead pipes, and other oddities. The exterior superstructure of Sigil is obviously something like uniform metal, but what lies between that metal and the patina of city on the inner face is mysterious.

Razorvine

According to In The Cage: A Guide to Sigil:

Razorvine is a curse and a plague for most Cagers: A cutter trims it back, poisons it, burns it--and it just keeps growing. Its diabolical twists and knots make it impossible to tell how many vines a cutter needs to slice to finish a plant off. Some cutters use the stuff when they set up “toll-stations” in dark alleys or the back streets of the Hive--it can grow several feet a day, so these turn-spike tolls can spring up overnight. Touts just talk about the plant and point it out to tourists, who are sometimes fools enough to try hacking off a souvenir.

Fact is, what a berk does with razorvine gives a cutter a pretty good idea of what kind of man he is. It’s useful as a sentry to keep unwanted intruders out of places they're not welcome. A few animals can eat the leaves; the vine can be grown as forage for these creatures. In the last of its peaceful uses, it can be dried and used as firewood. In a more evil vein, it can be used as a whip, a binding rope, or an effective garrote.

Razorvine’s a fact of life in Sigil. A single plant can have from 2-20 separate vines, all linked to a common root system. Its leaves are small, heart-shaped, and so dark as to be nearly black--they grow in dense clumps near the stem on wiry springs, but in fact the serrated leaves are completely harmless. The triangular stems are the danger: handling them inflicts damage unless the cutter is very careful. (p. 7)

Razorvine is not known to the general public to blossom very often, if at all. Allegendly, razorvine produces a red flower that resembles something between a rose, lily, and carnation.

Sigil Station

Beginning in January 2017, Sigil began transforming. This included the construction of the Multistar and the appearance of the Maelstrom. See: Sixth Reset

Wildlife

According to In The Cage: A Guide to Sigil:

Though most any breed of animal appears in Sigil sooner or later, very few can snatch a living from canny bashers--the animals must compete with the collectors, ragmen, and other human scavengers. Cranium rats have their own niche, roaches and the like do well, and the night-stalking, two-headed Aoskian hounds are found nowhere else. Cranium rats still bring a 3-gp bounty from the Office of Vermin Control. Aoskian hounds cost 20 gp (weaned) to 150 gp (grown and trained). They were first bred by followers of the god Aoskar. The power's been destroyed and nearly forgotten, but the hounds are thriving.

Sigil's only two native birds are a gray-green pigeon and a type of gray-bodied raven with black wings and head. The latter's called the executioner's raven because of its fondness for the easy meals found at the block, gallows, and stake. Some say that feasting on the flesh of fiends and the blood of slaadi accounts for these ravens' enormous size. Certain of the largest birds are said to speak. Rumors of a flock of local wereravens have neither been confirmed or denied. (p. 6)

Executioner's ravens are known to peck at an enemy's eyes.

The warning bark of an Aoskian hound is loud enough to stun opponents (Wis Save DC 15 or Paralyzed 1d6 rounds). The blood of Asokian hounds is used in creating Mordenkainen's Faithful Hound and Hold Portal scrolls, as well as other magics relating to doorways.

Wards

Clerk's Ward

Guildhall Ward

Hive

Lady's Ward

Lower Ward

Market Ward