The rather uncommon nalfeshnee are powerful demonic terrors that stalk the 400th layer of the Abyss: the Mountain of Woe. Their power is derived from their evolution through the terrors of the Abyss, which involves untold millennia of suffering (both given and received).
Tanar'ri Physique: incredibly powerful demonic life forms, the nalfeshnee are true tanar'ri. These fiendish creatures possess a wide array of supernatural, psionic, and even deionic abilities with which to torment lost souls, including the following:
* Darkness (a): all tanar'ri have the ability to share the inherent darkness of their very souls with the world at large. This rudimentary power functions only at intensity 4, but basically 'blacks out' everything within near missile distance of the nalfeshnee.
* Dimensional Transit (i): in addition to being able to teleport, tanar'ri can transition between planes of existence. They may do so with intensity 5 ability, though on a failed action dimensionally transiting tanar'ri may be subject to error, per a failed teleport. *
* Infravision (w): many of the Abyss' countless layers are dark beyond mortal ken, and have never seen the light (physically or otherwise). As such, all tanar'ri have evolved the ability to see by heat as well as by visible light, and can do so with intensity 5 skill.
* Invulnerability to Fire, Electricity, Heat, and Poison (s): the tanar'ri are hardy creatures - they have to be to survive at all in the endless, horrific wastes of the Abyss. Nalfeshnee in particular possess immunity to fire, electricity, heat, and poison.
* Portal Sense (w): planar beings all, nalfeshnee have the ability to perceive the various rifts that dot the planescape of the multiverse. Most of these doorways are invisible to the naked eye, but all nalfeshnee can spy them with ease, doing so with intensity 8 ability.
* Resistance to Cold and Physical Attack (s): while they're not immune to the effects of these attack forms, tanar'ri are considerably resistant to such. When exposed to any form of cold or physical attack, a nalfeshnee may resist such as if their Strength were +2 higher (intensity 8).
* Resistance to Magical Attack (s): nalfeshnee are incredibly powerful creatures of chaos. They are thus highly resistant to efforts by others to impose their own reality upon them, and as such can resist magical effects and damage at a whopping intensity of 21 (+5)!
* Telepathy (w): almost all tanar'ri are able to communicate directly from mind to mind - a vital skill when so few speak the same tongue. They can usually broadcast and receive thoughts with intensity 5 skill, enough to get their point across when necessary.
* Teleportation (i): chaotic creatures all, the tanar'ri can bend space itself to their will. All tanar'ri possess the power to teleport with intensity 10 ability, and can avoid teleportation's usual side effects while transporting themselves within the same plane of existence. *
Additional Limbs / Wings (a): curiously, the nalfeshnee bear small, angel-like wings that they can use to fly - despite their ponderous bulk. These magically empowered appendages give nalfeshnee intensity 1 flight, allowing them to move through the sky at 30 miles per hour.
Attenuation (i): a nalfeshnee can bolster its apparent intellect by reducing that of others in its vicinity. This intensity 13 power reduces the Intellect of others for an aura duration by its own intensity (minimum of 1), if the nalfeshnee passes an easy difficulty Attenuation (intellect) action.
Bands (a): nalfeshnee may use this spell-like power to issue forth bindings that are web-like in appearance - but much stronger. They work at intensity 13, easily trapping most conventional opponents, and last as long as they are concentrated upon.
Claws (s): the nalfeshnee all possess short, gnarly claws with which they can rend opponents. They can use these ill implements to inflict +2 slashing damage in hand to hand combat if they wish, though they usually prefer to wield their magical powers instead.
Cold Generation (a): nalfeshnee have the power to generate bone-chilling cold, which they can inflict upon others by touch. They may do this with intensity 13 ability, inflicting like energy damage with each frigid grasp (or other melee assault) as a contingent action.
Disguise (a): while they cannot shape change proper, the nalfeshnee can distort their appearance somewhat. They may assume the guise of any humanoid being they wish, though of course their immense height and bulk are somewhat hard to disguise (intensity 13).
Electricity Generation (a): while their cold powers only function with physical contact, the lightning bolts of a nalfeshnee are much more deadly. These intensity 13 discharges can strike anyone within near missile distance, and inflict energy damage with each hit.
Emotion Control / Fear (w): nalfeshnee can, if they spend an entire exchange producing the effect, create a beam of rainbow-like light. This light causes all within the nalfeshnee's area to wander aimlessly for an aura duration, facing their greatest fears all the while (intensity 13).
Fangs (s): like almost all tanar'ri, nalfeshnee possess sharp teeth with which to rapidly dispense foes - and consume them if desired. Nalfeshnee have both regular fangs and large, boar-like tusks for this purpose, which they can use to inflict +2 slashing damage.
Forgetfulness (w): wielding staggering powers of the mind, a nalfeshnee may carefully edit the memories of others. They can do so with intensity 20 ability, which lets them delete up to twenty minutes of an opponent's current memories at a time.
Growth (a): nalfeshnee stand at twenty feet tall. This gives them the growth power, by default, at intensity 5. Nalfeshnee thus have a +5 Strength score against normal-sized foes, while their Agility is also treated as if it were -5 in intensity.
Growth / Others (i): oddly, nalfeshnee have the ability to enlarge ordinary insects in their vicinity. This power, limited solely to such life forms, allows them to grow the things immensely, doing so with intensity 25 ability (making them sixty four times larger).
The effect of this is that, creatures formerly thought of as mere pests take on a new dimension, since they now have a size equal to that (or very close to, at least) normal humans. This allows them a staggering amount of lethality - particularly if they catch foes by surprise.
Imaginary Doubles (i): nalfeshnee have the curious ability to generate an imaginary, pretend double of themselves. This double is immaterial and cannot attack others at all, but the nalfeshnee can see through its eyes and hear through its ears. This is an intensity 1 power.
Invisibility (i): though mostly useless against other tanar'ri, nalfeshnee can use this intensity 13 ability to great effect against mere mortals and others who cannot perceive the infrared spectrum. This power lets them avoid visual detection entirely!
Nonapparent Vision (w): at will, a nalfeshnee can activate this sensory capacity in order to see something as it truly is. This intensity 13 ability easily allows them to pierce the veil of disguise, whether physical, mental, spiritual, or otherwise.
Paralysis (w): in addition to their ability to freeze an entire group of people with fear, nalfeshnee can concentrate their mental power on a singular foe, freezing them in their tracks. This works if they pass an easy difficulty Paralysis (willpower) action with this intensity 13 power.
Philosophical Sense (w): another of their useful sensory powers, nalfeshnee have the ability to 'feel' the philosophical bent of any person, place or thing they observe. They can sense something's leanings towards order, chaos, good, evil, or balance with intensity 13 skill.
Reanimation (i): in addition to summoning forth weaker tanar'ri to do their bidding, nalfeshnee can literally create reinforcements - most often from the bodies of fallen foes! They can build zombies or skeletons out of corpses, a skill they wield with intensity 13 ability.
Revival (s): like other true tanar'ri, nalfeshnee can sometimes give death the laugh. Unless killed inside the Abyss or eaten, a nalfeshnee may attempt to reconstitute itself on its home plane with this intensity 5 power. The difficulty involved, of course, depends on how it died.
Summoning (i): a nalfeshnee may summon forth their fellow tanar'ri in great numbers, and somewhat often - though they usually rely upon their own, considerable power. Twice a day, they can draw forth one vrock or from one to six babau, doing so with intensity 5 ability.
In addition to the above, considerable array of supernatural powers, nalfeshnee are also equipped with natural psionic abilities. These capabilities will vary from nalfeshnee to nalfeshnee, but will usually be of either a metapsi, psikinetic or psipathic bent, most often being destructive in nature.
Hindrances / Augmentations:
Monstrous: it should go without saying, but nalfeshnee are monstrous entities - just look at them! Nalfeshnee are at Willpower 0 to prevent Edge 0 humans from fleeing at the mere sight of them - not that they would ever really bother, for such creatures are their playthings.
Susceptibility: like all tanar'ri, nalfeshnee are weak against the use of cold-wrought iron weapons, as well as holy water and weapons. Their supernatural defenses are ineffective against such assaults, which inflict at least a quarter of their maximum Health in damage.
World Domination: the nalfeshnee would be behind the Blood War effort more if they were in charge. To this end, they act to sabotage all the balors' plans in regard to this conflict, in order to ultimately take them down and replace them with, well, themselves.
The small number of nalfeshnee are all haughty and arrogant. They are assured of their own superiority and self-importance, to the point that they scheme to get their way no matter what effect it has on other tanar'ri or the Blood War effort - they care only for themselves.
Their extreme intellects make them very dangerous in this regard, for while chaotic and mad, the nalfeshnee can nonetheless plot and plan with the best of them, and can usually succeed intellectually where their physical might would otherwise fail them.
Nalfeshnee are monstrous. They are twenty feet tall, and resemble a horrible cross between a boar and an almost hairless ape. They have claws, tusks, tails, and strangely glowing red eyes, which appear to look through those who meet the nalfeshnee's gaze.
Nalfeshnee are very powerful tanar'ri - just below the balors in raw strength. However, their superior intellect recognizes that, while a direct confrontation with balors would be rather unsuccessful, nalfeshnee can hobble their physical superiors with sabotage.
Most nalfeshnee will do this whenever they can, doing their level best to lay balors low in any way possible. This is one way in which they inadvertently extend the everlasting Blood War - their plots to foil the balor's plans tend to cripple the tanar'ri effort as a whole.
At the same time, they are responsible for choosing which petitioners the tanar'ri will use to create more of their kind - if such don't evolve into tanar'ri on their own eventually anyway. They do this from their lair on the 400th layer of the Abyss, the Mountain of Woe.
There, the nalfeshnee judge all petitioners that arrive in the Abyss - at least, those who survive long enough to be transported there. From their flaming thrones, these giant fiends use their fear powers to somehow feed upon the thoughts of the petitioners, leaving them as desiccated husks.
These soul husks are then formed into differing forms of tanar'ri, depending on the nalfeshnee's whims.
* Depending on which version of the Planescape lore you wish to use, the nalfeshnee (along with the rest of the tanar'ri) may not have access to this power any longer, having lost it due to yugoloth meddling. Its presence is at the discretion of the individual Narrator.