The lone wanderers of the Abyss, rutterkin are tanar'ri of the least sort. They are sometimes formed from petitioners, but can also be the result of manes or dretches who grow in power and awareness over time. They are demonic entities possessing supernatural powers.
Tanar'ri Physique: while they are generally shunned by most tanar'ri, rutterkin are considered members of that race. Evolved from the chaotic and evil larvae of the Abyss or powerful manes or dretches, rutterkin are true planar entities, and possess these tanar'ric capabilities:
* Darkness: all tanar'ri have the ability to share the inherent darkness of their very souls with the world at large. This rudimentary power functions at only Poor (4) rank, but basically 'blacks out' the area a rutterkin currently occupies (it works within Near range).
* Damage Reduction / Cold: though they are not immune to the effects of cold, tanar'ri are considerably resistant to the stuff. When exposed to any form of cold damage, a tanar'ri may reduce its intensity by 2 CS - applying this reduction even before other defenses.
* Damage Reduction / Magic: 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. Rutterkin possess 1 CS protection against all forms of mystic assault.
* Dimensional Transit: in addition to being able to teleport, tanar'ri can transition themselves between planes of existence. They may do so with Good (10) ability, though on a failed FEAT roll dimensionally transiting tanar'ri may be subject to error, per a failed teleport. *
* Infravision: 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 Good (10) ability.
* Invulnerability to Fire, Electricity, Heat, and Poison: 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: planar beings all, rutterkin 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 rutterkin can spy them with ease, doing so with Excellent (20) ability.
* Telepathy: 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 at Typical (6) rank, enough to get their point across when necessary.
* Teleportation: chaotic creatures all, the tanar'ri can bend space itself to their will. All tanar'ri possess the power to teleport with Remarkable (30) ability, and can avoid teleportation's usual side effects while transporting themselves within the same plane of existence. *
Claws: rutterkin bear barbed, gnarled claws with which they can inflict Edged Attack damage, but usually prefer not to use them, as doing so causes pain to their malformed bodies. They must pass a yellow Psyche FEAT to act in the round after using their claws in combat.
Emotion Control / Fear: a rutterkin may, upon touching a foe, instill great fear within them. This requires they make successful contact in melee, at which point the target must pass a Psyche FEAT roll against Remarkable (30) rank or quiver in fear (or flee) for 1d10 turns.
Flight: the hated rutterkin possess the power of flight! They can soar over the terrain as they see fit, doing so at approximately thirty miles per hour. This translates into Feeble (2) ranked flight, but they may do so as often as they wish - if not constantly.
Summoning: once per day, rutterkin may summon forth 'least' tanar'ri. This Typical (6) ranked power may draw manes, dretches and rutterkin to the summoner - up to eight at once. Roll a second FEAT to determine how many arrive, if successful; white is 2, green is 4, etc.
Telekinesis: as can the teeming masses of dretches, rutterkin may impose their will on matter within their vicinity. Up to three times per day, they may wield this supernatural ability at Typical (6) rank, allowing them to handle up to 200 lbs. of matter remotely.
Limitations / Enhancements:
Susceptibility: like all tanar'ri, rutterkin 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 a rutterkin's maximum Health in damage.
Double Crescent Polearm: rutterkin often carry these long weapons with them. They can be used to inflict their Strength rank +1 CS in Edged Attack damage with these double-bladed pole weapons, and can use them to strike non-adjacent foes as well (10' reach).
Flatchet: rutterkin often carry these broad-headed swords with them into battle. Long and flat, the shape of this blade allows them to inflict their Strength rank +1 CS in Edged Attack damage against their foes, though this is boosted a further +1 CS against unarmored foes.
Snap-tong Device: rutterkin often wield these spring-loaded jaws in battle. They inflict their Strength rank in Edged Attack damage, but will then lock onto a foe and keep inflicting like damage until their target can break free (Good (10) Strength FEAT) or dies.
Three Armed Blades: rutterkin often carry these projectile weapons with them. They may be flung at a target with the aid of a sling-like device, and will spin and speed at a foe to inflict a rutterkin's Strength rank in Edged Attack damage with each successful hit.
Unattractive 2: rutterkin are horrible, malformed things. They appear generally humanoid in size and shape, but the proportions are all twisted and warped. This makes them suffer a -4 CS to reaction rolls, not that they mind really - they only care about themselves.
Weapon Skill: though generally ineffective in the use of their natural weapons, rutterkin usually demonstrate some measure of skill in their choice of weapon(s) - most often at least one of the four listed above. They should wield them at their Fighting score +1 CS.
Rutterkin are generally solitary creatures, shunned by other tanar'ri for reasons unknown. These pathetic beasts wander the Abyss left to their own devices, which allows them to vent their rage upon any non-tanar'ri and tanar'ri weaker than themselves (manes and dretches) mercilessly.
The rutterkin resemble malformed humanoids. They possess dusky skin, sparse hair, and typically don't bother with clothing. They have gnarled claws which they generally do not wield, as well as pointy skulls, pointy, swept-back ears, and extremely sparse body hair.
Rather ugly in the face, rutterkin are deformed significantly. Their bodies possessed warped proportions, and a limb or body part on one side of their frame is often of differing size than the 'matching' part. They are often gaunt and bulky at the same time, just in different areas.
The rutterkin wander the Abyss alone, for the rest of the tanar'ri want nothing to do with them for some reason. It is rumored that this is because they are formed from larvae that were especially evil - but especially incompetent - in their former, mortal lives.
Of course, this is but one way a rutterkin may form in the Abyss. Sometimes they come into being when manes or dretches evolve or grow in power. They can also 'just happen', as is often the case on the planes of mad hatred; chaos unbound causes this sort of thing.
In rare cases however, rutterkin are the result of humanoids from other planes who, after being trapped so long in the Abyss, simply mutate into tanar'ri by overexposure to the ambient chaos and evil. Becoming a part of the madness around them, these beings are utterly insane.
* Depending on which version of the Planescape lore you wish to use, the rutterkin (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 Judge.