Nabassu are greater tanar'ri, demons of great power hailing from the Abyss. These monsters possess a vast amount of supernatural powers of a distinctly evil sort, along with a variety of physical modifications that make them supremely deadly against ordinary human foes.
Tanar'ri Physique: the nabassu are the first form of greater tanar'ri, beings who have likely suffered (and inflicted like) beyond measure to get where they are. Nabassu are true planar entities, and possess these tanar'ric capabilities:
* 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 nabassu.
* 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. Their forms have evolved over time to give them complete immunity to fire, electricity, heat, and poison.
* Portal Sense (w): planar beings all, nabassu 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 nabassu can spy them with ease, doing so with intensity 8 ability.
* Resistance to Cold Attacks (s): though they are not immune to the effects of cold attacks, tanar'ri are considerably resistant to them. When exposed to any form of cold in their environment, a tanar'ri may resist such as if their Strength were +2 higher (intensity 8).
* Resistance to Magic (s): furthermore, most tanar'ri possess some degree of resistance to magical attacks, whether they come in the form of environmental effects, spells, or even magic items. Nabassu possess intensity 15 (+3) protection against all forms of mystic assault.
* Resistance to Physical Attacks (s): furthermore, nabassu are highly resistant to physical attack, above and beyond what their 'natural' Strength would offer. They may shrug off the effects of physical damage as if their Strength were +1 (intensity 4).
* 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): nabassu possess large, leathery wings to complement their taut, leathery frame. These wings bear the nabassu aloft with intensity 3 velocity, meaning they can soar about at a maximum speed of ninety (90) miles per hour under favorable conditions.
Claws (s): the nabassu wield m.s. 12 claws on both their hands and their feet, and can use either as they see fit - assuming they lack a weapon in hand. Nabassu may wield these 'natural' weapons to inflict their Strength +2 in slashing damage.
Death Gaze (fledgling) (w): the stand-out, intensity 5 power of fledgling nabassu, this ability allows them to hideously transform mere mortals. A nabassu may transform its target into a ghoul (or ghast) if it can pass an average difficulty Death Gaze (willpower) action against them.
This process takes days. Every day, the victim must pass an easy difficulty Strength (death gaze) action or lose one point of such, until they reach a Strength of zero (0). This process continues for ten days; if the target has not died by this time, they will recover (and are not transformed).
During this period, the victim is increasingly compelled by a desire to consume human flesh. This compulsion becomes a necessity after they die and rise again as a ghoulish monster, having been transformed into an undead creature that subsists solely on human flesh.
Fangs (s): like their claws, a nabassu may wield its fangs in battle in order to inflict their Strength +2 in slashing damage. This damage comes in the form of a painful bite, and helps a nabassu to quickly consume its victims in order to steal their power!
Intangibility (mature) (a): twice per day, a mature nabassu may render itself completely immaterial. A nabassu in this state is nigh-invulnerable to mundane physical and energy attacks (intensity 15), though they are affected normally by the other six attack vectors.
Paralytic Field (mature) (w): mature nabassu possess a powerful defense in the form of an intensity 6 paralytic field. If the nabassu can pass an easy difficulty Paralytic Field (willpower) action against anyone entering near missile distance, it can paralyze them for an aura duration.
Regeneration (mature) (s): fully developed nabassu are incredibly hard to dispatch, for they can quickly heal even the most severe of wounds. They regenerate with at intensity 7, meaning they recover a lost card of Health on a positive aura draw or neutral aura draw of 6 or less.
Sound Control (i): nabassu wield a limited form of this power that allows them to dampen all sound in their immediate vicinity. Functioning within near missile distance, this intensity 7 power lets them silence any noise they (or their victims) might be making.
Summoning (mature) (i): the nabassu have several summoning powers, both of which function at intensity 5. Three times a day, they may attempt to summon forth fellow tanar'ri. An easy difficulty action brings forth an entire horde of manes.
Draw two cards and add the sum to determine an amount of manes that answer the nabassu's call. An average difficulty action summons forth one to five cambion (draw a card and divide by two), and a challenging difficulty action will make manifest another nabassu.
Similarly, they have an additional special power while in the Abyss. This lets them, without cardplay, bring from one to five ghouls or ghasts to their side, possibly being undead monstrosities that they themselves have created in the past, depending on their actions.
Vampirism (i): in both of their stages of development, a nabassu possesses this power - though it is expressed differently in each. In their fledgling form, a nabassu uses it to devour the body and soul of its victims, adding a point to Strength or Willpower for each five kills.
A nabassu may add 3 points to each of these ability scores in this manner, and when they have absorbed the maximum amount of points in each, they are considered 'mature'. They lose their death gaze power, but gain several others in the process, 'trading up' significantly.
Once they are mature, a nabassu can instead drain a victim on touch, directly siphoning off their life energies to supplement their own. Nabassu wield this power at intensity 6, and can use the Health siphoned off from their foes to recover their own lost Health points.
Hindrances / Augmentations:
Monstrous: it should go without saying, but nabassu are monstrous entities - just look at them! A nabassu is at Willpower 0 to prevent Edge 0 humans from fleeing at the mere sight of them - not that they would ever really bother, for nabassu thrive on terror.
Susceptibility: like all tanar'ri, nabassu 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.
Melee Weapons (s): while they have powerful claws, a nabassu often opts to wield a melee weapon instead, for additional damage. They can carry such weapons in order to inflict their Strength +4 in bashing or slashing damage, depending on the weapon's nature.
Stealth (w): even without their abilities to dampen sound, the nabassu are masters of stealth. They generally impose an increased difficulty upon actions to detect them, as they're able to move quietly and inconspicuously despite their form, and actively avoid being tracked.
Demolisher: there's no two ways about it, the nabassu are the perfect fit for this calling. They are not mindless beasts, instead inflicting the maximum amount of damage, both physical and mental, to mortals with their rampages - the better to be remembered by!
The masses of nabassu are destruction incarnate. They rage and roil against anything and everything they can, both for the sheer pleasure of it and because it furthers their eventual aims in the Abyss. They are encouraged to terrorize mortals, and enjoy little else in their existence.
The nabassu has a sufficiently 'gothic' appearance. It stands seven feet tall, and is wiry and gaunt. Its leathery gray skin seems barely able to contain the wiry muscles beneath. They possess large, bat-like wings, as well as long claws on each appendage, and tusk-like fangs.
Nabassu are greater tanar'ri, which sometimes occur through natural breeding, but are most often a result of lesser tanar'ri growing in power and 'evolving' to this state of existence. They can manifest spontaneously in the Abyss but this is somewhat unlikely for their kind.
They possess a curious susceptibility to being summoned, and a spell to draw forth demons, unless more specific in its targets, is most likely to collect one of them. Once drawn away from the Abyss, they do everything they can to escape their summoner, in order to rampage unopposed.
You see, nabassu live to spread the terror of the Abyss across the planes, in order to make mere mortals attach fear, dread and terror to the tanar'ri name. This belief fuels the tanar'ri's power throughout the multiverse, and is a tangential effort to ultimately win the Blood War.
Once free of a summoner, they kill and consume as many victims as is possible, body and soul, in order to increase their own power. Their aim is to maximize their growth to full maturity before they return to the Abyss, either to await additional summons or to ascend further.
* Depending on which version of the Planescape lore you wish to use, the nabassu (along with the rest of the tanar'ri) may not have access to these powers any longer, having lost them due to yugoloth meddling. Their presence is at the discretion of the individual Narrator.