In Sigil the streets teem with denizens of a thousand planes, and each claims to have visited a thousand more. In every back-alley gambling haunt in the Lower Ward, in half the tiefling halfway houses, in the incense-heavy air of vapor shops where old men debate weird philosophies, tales pass back and forth. Those tales debate the absolutes of the Outer Planes, the greatest and least, loftiest and most base, best and worst. Every tale that turns upon the worst inevitably stops with the place of despair, the infinite bleak layers that represent the suffering and toil of existence made tangible. There chaos and hopelessness reign.

There in the Abyss, where others endure endless torment, the tanar’ri thrive.

Like the baatezu, tanar’ri are fiends (lower planar creatures of enormous power), but they embody evil of a different type. Baatezu, lawful evil beings, pursue calculated doctrines as part of a grand plan to advance their race to dominion of all the planes. Most baatezu tempt mortals into intellectual evils such as pride, ambition, and subversion. Tanar’ri, chaotic evil personified, are motivated not by doctrines but by insane, violent inner drives. They tempt mortals into crimes of passion and vice, evils of appetite. Less intelligent tanar’ri often attack without question and fight until slain. True and greater tanar’ri roam the Astral and Ethereal planes, driven ceaselessly to seek fresh victims.

Combat: All tanar’ri (even the least) share the spell-like powers darkness, 15’ radius, infravision, and teleport without error. They also can gate in other tanar’ri at will, as defined for each type. Tanar’ri are affected by attack forms as noted below:

All tanar’ri have a form of telepathy that lets them communicate with any intelligent life form regardless of language barriers. Tanar’ri with Average or better Intelligence can converse.

The Abyss-forged magical weapons of the tanar’ri dissolve upon the owner’s death. When one doesn’t, the weapon probably originated elsewhere.

Habitat/Society: The tanar’ri have five divisions, listed here in order of ascending power with member varieties:

Least: dretch, manes, rutterkin

Lesser: alu-fiend, armanite, bar-lgura, bulezau, cambion, maurezhi, succubus, uridezu, yochlol

Guardian: molydeus

Greater: babau, chasme, goristro, nabassu, wastrilith

True: alkilith, balor, glabrezu, hezrou, marilith, nalfeshnee, vrock

These classifications actually mean little in their lives. They are merely broad estimates of destructive power. The tanar’ri have little use for anything besides power, and a strong lesser tanar’ri who bests a greater cousin gains higher status in the Abyss. Their petty battles for position are endless. The only class free from these power struggles is the molydeus, a guardian tanar’ri that seems curiously divorced from the tanar’ri power structure.

There are also the spyder fiends, a subrace of the tanar’ri.

The tanar’ri are one of the two major factions in the Blood War. For as long as the tanar’ri have existed, they have waged war against their ancient enemies, the baatezu. The tanar’ri and baatezu wage war in strikingly different ways. The baatezu are organized and fight their battles with planned tactics for strategic goals. The tanar’ri, however, are a horde of chaos and disorder, using their endless numbers in wars of attrition. It is difficult to estimate tanar’ri populations, considering they inhabit an infinite number of infinitely large planes, but there are easily 100 times as many tanar’ri as baatezu. This disordered race wages the Blood War only because true tanar’ri seem to have a primal urge to destroy baatezu. They force those less powerful than themselves to serve their wishes.

Ecology: Most tanar’ri feed on either flesh or the life force of other living beings. It appears that they derive more nutrition from a victim by instilling terror in it before the kill. Whereas most predators simply stalk and then kill, tanar’ri add a third step: stalk, terrify, kill.