the Tanar'riIn the darkest depths of the infinite layers of the Abyss, terrible creatures fester. Whether born from the cast-off spiritual remnants of chaotic and evil mortals, from frenzied inter-breeding amongst themselves, or even from the bedlam of the Abyss itself, the tanar'ri rise. Mad passion and dark desire made manifest, the tanar'ri are perfect reflections of their home plane, each a horror like no other.
While many tanar'ri share similar forms, this is because these demonic entities have learned what shapes help them survive their home, mostly through evolutionary trial and error on an infinite scale. And to survive in the Abyss, the tanar'ri must be willing and able to kill anything and everything they can... and not only are the tanar'ri capable of this, but they relish each opportunity.
Each tanar'ri has suffered and inflicted more suffering than you can possibly imagine, for it is all they know. The more powerful amongst them abuse their lessers at the slightest whim, because who is to stop them? The less powerful tanar'ri withstand this punishment in the hopes of returning the favor someday, and in turn take out their aggression on anything they perceive to be weaker than themselves.
But why do the tanar'ri act so? Each and every tanar'ri, from the only slightly sentient dretch to the mighty Abyssal lords themselves, feel that they know the Answer, the singular truth behind not only their lives, but of existence as a whole. They each try to teach the other tanar'ri the tenets of this Answer, but the fiends are so fiercely independent that they shout each other down, thus causing the current situation.
And that's before you consider the baatezu. While the tanar'ri rant and rail against each other for attempting to force their Answers upon each other, the baatezu, hated creatures of law, attempt to impose their own twisted order across the whole multiverse. This alone is the reason the tanar'ri can unite, (sometimes) casting aside their differences to ward off the orderly devils before their Answer wins out.
The Blood War is the result of this conflict, the quintessential clash of order and chaos in the lower planes. The tanar'ri and baatezu constantly wage war to determine the fate of the multiverse, the former refusing to accept that anyone but they know the Answer to why they exist, while the latter insist that they are Right. Naturally, this is a war that neither side can really win, and has waged for millennia.
Tanar'ri Origins and Evolution
The tanar'ri, as stated above, generally originate from three separate sources. They most often come from the souls of deceased mortals of chaotic and evil mindsets, landed in the Abyss in the form of despicable larvae. While some manifest in more advanced forms, such as manes, dretches or rutterkin, few entities are possessed of sufficient evil to arrive on the plane in any form other than that of a larvae.
Of course, the tanar'ri are mercurial and passionate creatures, and often breed - it's one of the few things they do with each other that doesn't involve murder. Breeding usually produces a new tanar'ri that is of equal station or some midway between the two levels of its parents' evolution, unless true tanar'ri breed; this results in lesser forms as only the true tanar'ri have experienced and dealt enough suffering to attain that level.
Finally, tanar'ri occasionally just spring into existence from nothingness. A plane of roiling chaos and selfish evil, the Abyss only loosely follows the 'rules' of causality that we take for granted, and sometimes it just spits out whole lifeforms at the drop of a hat. These new tanar'ri are never manes, which are still technically petitioners, and are most likely dretches or rutterkin, but are sometimes more powerful.
Once a tanar'ri is present in the Abyss, it will evolve or die. Tanar'ri grow in power by convincing others that it is stronger than they, whether by demonstrating this with direct action or faking it with trickery and treachery. When it truly believes it is better than its fellows, and enough of said fellows also believe this, a tanar'ri will slowly change, its form evolving in one of several fashions.
There is no set 'pattern' to this, as there is in Baator, no 'lessons' to be learned from each form, as with the yugoloths. A tanar'ri is as powerful as it believes it is, and while they most often move from their existing form to one that is only slightly more powerful, sometimes a tanar'ri can jump through the 'ranks' to a significantly more powerful configuration if it possesses exceptional capability.
This happens with greater frequency on particularly hostile planes where one tanar'ri form is more suited to survival than any others. But not always. With the tanar'ri, it's hard to pin them down into categories or rules - they are creatures of chaos as much as they are entities of evil. Sometimes a dretch may fight hard and become a rutterkin, or instead evolve into a bar-lgura. Who knows?
Common Tanar'ric Powers
Though they are highly chaotic creatures, and sometimes are in fact unique compared to their brethren, the tanar'ri have developed a standard set of supernatural abilities thanks to their time in the Abyss. Untold millennia of evolution in the harshest environs possible have imprinted these demonic powers onto (almost) each representative of the tanar'ri species, and no matter what other powers they have, all tanar'ri wield these:
Darkness (a): creatures of blackest evil, the tanar'ri have the inherent ability to share the inner darkness of their souls with the world at large. This isn't an especially potent ability, working only at intensity 4, but thanks to this power a tanar'ri can easily blanket everything within near missile distance with an inky blackness of the supernatural sort - even powers like infravision may fail within.
Infravision (w): a large number of the Abyss' countless layers are dark far beyond mortal ken, and have never seen the light (either metaphorically or otherwise). As such, the tanar'ri as a whole have developed the means of seeing by heat as well as light, though this sense can be confounded by enough tanar'ri emitting their darkness in tandem. This power works with intensity 5 ability.
Invulnerability to Fire, Electricity, Heat and Poison Attacks (s): the tanar'ri are incredibly hardy creatures - they have to be to survive at all in the endless, horrific wastes of the Abyss. The demonic creatures possess complete immunity to these forms of damage, regardless of their source; whether ambient in the environment or applied as an attack form, these phenomenon do not affect the tanar'ri.
Portal Sense (w): all the tanar'ri beyond the manes level of development (i.e., the weakest) are true planar beings. As such, they have the 'spark' of the planes within them, and can perceive the subtle differences between one universe and another. This allows them to see portals between one realm and another, whether on layers within a plane or between two different planes entirely, with intensity 8 ability.
Resistance to Cold Attacks (s): though they are not immune to the effects of this kind of damage, all tanar'ri possess considerable resistance to it (on top of any other protective abilities they may wield). When exposed to cold effects in their environment, a tanar'ri benefits from intensity 8 (+2) protection from it, making the dread chill of winter much less effective against these fiends.
Resistance to Magic (s): furthermore, most tanar'ri possess powerful resistance to the effects of magic, themselves being so chaotic in nature. The strength of this power varies from tanar'ri form to tanar'ri form, but almost all of the beasts bear at least intensity 4 (+1) resistance against magic, sometimes even more. This applies to either magic energies, spells, or even enchanted items.
Telepathy (w): finally, all tanar'ri beyond the manes level of development are truly sentient beings, and thus can wield this power. Since few tanar'ri actually speak the same language, direct mind-to-mind communication is the only way they can really convey messages, ideas and (usually) threats to each other, and the tanar'ri may wield this supernatural power with intensity 5 skill.
Other Tanar'ri Dis/Abilities
Complementing the extensive supernatural capabilities common to all tanar'ric beings, these demonic lifeforms also possess several other powers and weaknesses. The enterprising planewalker will keep them in mind whenever they intend to go toe to toe with these horrific monsters of murder and mayhem, or even if they don't; you never know when these chaotic terrors will turn up out on the planes.
Stolen Powers: for the longest time, the tanar'ri possessed the power of teleportation. They could easily transport themselves almost anywhere within their current plane of existence, doing so with intensity 10 ability, and without fail or error. Similarly, they could dimensionally transit their bodies to other planes of existence with intensity 5 skill, though they risked teleport errors on a failed action.
In some versions of the Planescape lore (the later publications), it was revealed that these powers were granted by a strange creature controlled by the yugoloths, and subsequently taken back. A tanar'ri could regain the use of these powers by submitting itself to yugoloth rule, which meant that those neutral fiends would forevermore wield power over said tanar'ri's souls. Naturally, this wasn't well received by the tanar'ri.
If you follow this plot line, individual tanar'ri won't have these two powers for the most part - unless either a) our intrepid fiend does indeed submit to yugoloth domination in exchange for it anew, or b) it re-evolves the power all by itself. While the former is more likely, the latter is a distinct possibility in the mad bedlam of the Abyss. Of course, if you don't follow this 'rule', they all still have these dangerous powers anyway.
Susceptibility: demonic creatures all, the tanar'ri are susceptible to the use of holy water, holy weapons, and cold-wrought iron weapons. The former inflicts its wielder's Willpower in karmic damage, while the latter two bypass a tanar'ri's defenses entirely. Attacks with these three items inflict either their normal damage or one quarter of the tanar'ri's maximum Health, whichever of the two would be higher.
Known Tanar'ri Forms
The following is a catalog of known tanar'ri types. While the Abyss has surely spat out many more demonic forms for the tanar'ri to possess, either as a sub-race or as unique entities, these are the forms the tanar'ri are most often found in. They are presented in approximate order, from the least to the most powerful. While also present in the Bestiary index, this list is assembled for convenience:
Manes: the spirits of particularly chaotic and evil dead made manifest in the Abyss, manes are the lowest form of tanar'ri - or just powerful petitioners. Weak and spiteful, they lash out as directed... or at anything crossing their path. Availability:
Dretches: when a manes shows a spark of self-awareness, if often grows into a dretch. The first form of 'real' tanar'ri, the teeming masses of dretches are small, dim-witted and petty, and long to rise from their lowly station. Availability:
Rutterkin: while rutterkin are stronger and smarter than the teeming hordes of dretches and manes, they are not used in Blood War efforts. No, for reasons unknown, the rutterkin are generally shunned by their demonic fellows instead. Availability:
Quasits: like manes, some argue that quasits aren't 'real' tanar'ri. They are formed from special larvae to aid in the temptation of mortals with deep, evil passions - and if they serve well, quasits can ascend into greater tanar'ri forms. Availability:
Uridezu: resembling hairless, bipedal rats of human stature, uridezu are rather low on the tanar'ri totem pole. They often perform various menial tasks for their more powerful brethren, or act as scavengers or rodent kings when left unattended. Availability:
Alu-fiends: the offspring of succubi and non-tanar'ri, alu-fiends posses of many of their mothers' abilities. They also have the skill to master sorcery, and often carry impresive magical items to make up for their physical weakness. Availability:
Cambion: the offspring of non-succubi tanar'ri and mortals, cambion are half-breeds born into a world that hates and fears them. Either in the 'real' world or in the Abyss, they are the subject of scorn because of their origins. Availability:
Armanites: seeming masters of the Abyss' 377th layer, the armanite hordes populating that plane resemble pale, undead centaurs. They wander the land in troupes, selling their services to whoever offers them enough plunder... and fresh meat. Availability:
Maurezhi: the ghoulish maurezhi stalk the multiverse in search of victims to consume. Those whose bodies and souls they ingest surrender everything they know, along with some personal power... allowing the maurezhi to grow even more terrible! Availability:
Succubi: eerily beautiful seductresses, succubi journey forth from the Abyss to exploit the dark passions of mortals. Succubi feed upon their energies directly, or often just abduct them to the Abyss to serve as slaves - or worse, food. Availability:
Yochlol: the so-called Handmaidens of Lolth, yochlol are specially transformed tanar'ri the drow goddess uses as personal servitors. These demonic terrors may take many forms, and roam the material planes when not in the Demonweb Pits! Availability:
Bar-lgura: strong resembling conventional orangutans, bar-lgura aren't much smarter than those mundane creatures. Of course, normal animals don't bear an arsenal of demonic powers, much less such sullen, blinding blinding rage...! Availability:
Bulezau: the rumored creations of mad tanar'ri lord Baphomet, the ill-tempered bulezau are hate-driven murder machines. Though somewhat concentrated in the 600th layer of the Abyss, one can find them all over that plane these days. Availability:
Nabassu: first of the 'greater' tanar'ri, Nabassu serve a curious role for their 'brethren'. They exist solely to spread the terror of the Abyss, eagerly waiting to be summoned forth in order to rampage across the multiverse! Availability:
Chasme: inhuman monstrosities, chasme are more mosquito than man. These blood-sucking insectoids flit about the Abyss, ceaselessly seeking out Blood War deserters and feeding upon them with the blessings of Abyssal lords. Availability:
Babau: babau assemble the vast tanar'ri armies required to wage the Blood War. They conscript their least and lesser cousins into the fight, while themselves avoiding the front lines as long as they can keep the 'recruits' coming. Availability:
Goristroi: hulking behemoths, goristroi often grow up to twenty four foot tall! They are a frightening cross between man and bison, with large ape-like arms, dreadful horns, and a voracious appetite that can strip land bare for miles! Availability:
Wastriliths: the so-called Water Lords, wastriliths are solitary stalkers of the deep. They prefer solitude in their cold, undersea lairs, and cheerfully attack and devour anything dumb enough to intrude upon their (huge) territories. Availability:
Vrocks: first of tanar'ri considered to be 'true' members of their race, the vulture-like vrocks serve as the Abyss' aerial defenses. When not acting as elite Blood War shock troops, they often hunting victims for sustenance - and fun. Availability:
Hezrou: hezrou are the tanar'ri's Blood War middle managers. They have free reign to interpret and execute the commands of their superiors as they see fit, - which is a necessity, as managing tanar'ri is similar to herding cats! Availability:
Glabrezu: towering fiendish terrors, glabrezu stand fifteen feet tall. These horrific creatures, with their doglike heads and superfluous limbs, readily answer summons by foolish mages in order to spread the Abyss' influence far and wide. Availability:
Alkiliths: wretched corruption personified, alkiliths are formless terrors that work to spread the horrors of the Abyss throughout the multiverse. They ruin everything they can get their pseudopods on, and delight in doing just that. Availability:
Mariliths: genius tacticians, the six-armed mariliths are incredibly dangerous. Even without their plethora of magical and psionic powers, mariliths are intractble foes, and are a match for almost anyone, mortal or otherwise. Availability:
Nalfeshnee: these immense, boar-like monstrosities are frighteningly intelligent and posses power just shy of the balors themselves. This makes the nalfeshnee endlessly plot and scheme for supremacy from their Mountain of Woe. Availability:
Balors: most powerful of the true tanar'ri, balors are few and far between. However, the blazing power they wield is enough to cow even the most arrogant tanar'ri into submission - further aiding their crusades against the hated baatezu! Availability:
Molydeus: the only known form of guardian tanar'ri, molydei are true tanar'ri who have been empowered by an unknown agency to further the Blood War effort - and these fanatical fiends have the power necessary to keep true tanar'ri on task! Availability:
Abyssal Princes and Lords: those rare few tanar'ri who live long enough, and gather enough power, can ascend past the known, common forms their race takes as they evolve, becoming unique. Even fewer of these rule a layer of the Abyss itself! Availability: