Like all tanar'ri, the molydei are demonic creatures of chaos and evil. They possess a wide variety of supernatural powers with which to do their duties, which are imposed on them (like their very forms) by whatever mysterious agency has created them.
Tanar'ri Physique: while they have been altered into their current configuration by parties unknown, the molydei are nonetheless tanar'ri. As such, they wield a wide variety of powers due to their demonic heritage, the most common of which include 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 molydeus.
* 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. Molydei in particular possess immunity to fire, electricity, heat, and poison.
* Portal Sense (w): planar beings all, molydei 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 molydei can spy them with ease, doing so with intensity 8 ability.
* Resistance to Cold Attacks (s): while not immune to cold, a molydeus is nonetheless quite resistant to it - possibly due to its infernal nature. When exposed to cold damage, a molydeus benefits from intensity 8 (+2) resistance to such attacks and environmental phenomenon.
* Resistance to Magical Attack (s): the process that creates a molydeus from other true tanar'ri renders them virtually impervious to magical assault. In game terms, consider a molydeus resistant at intensity 27 to sorcerous damage (+6).
* Resistance to Physical Attacks (s): an apt term to describe the molydei is 'nigh invulnerable'. These demonic horrors possess intensity 16 (+4) resistance to physical assault of all types, making them incredibly difficult to defeat in battle.
* 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 / Head (a): molydei all possess two heads. The first is a wolf's head, which is pointed forward, and is in the standard position. The second is a long, snake's head (with a considerable amount of 'neck') positioned behind the first head, which can swivel in any direction.
Animal Hybridization / Others (i): this rare ability allows a molydeus to transform others into animals of various types, doing so with an average difficulty action, opposed by the target's Strength. Those who are changed gain any of the natural abilities of their new form.
Bands (a): molydei may use this spell-like power to issue forth bindings that appear like shadowy black tentacles. They work with intensity 13 power, easily trapping most conventional opponents, and last as long as they are concentrated upon.
Charm (w): molydei possess the ability to charm a single target, per the spell of the same name. This skill lets them make temporary 'friends' of those they can pass an easy difficulty Charm (willpower) action against, until they attack or the victims can break free of it.
Danger Sense (w): the scant few molydei in existence are rarely, if ever, surprised by anything in their environment. They possess this supernatural awareness of their surroundings at intensity 13, which informs them of any dangers, active or passive, that threaten them.
Electricity Generation (a): up to seven times a day, molydei have the power to fire lightning from their very eyes! Each of these bolts of electric power will inflict intensity 13 stunning energy damage with each deadly strike - often enough to slay a body outright!
Emotion Control / Fear (w): the power of a molydeus corrodes the resolve of others. On contact, this fiend may instill within its foe intensity 13 fear with an easy Fear (willpower) action. If successful, the molydeus' target will either quiver in fear or flee in terror for an aura duration.
Fangs (s): both of a molydeus' heads possess fangs. They can be used to inflict +2 slashing damage in melee, but the snake's head is armed with a powerful venom that has a rapid transformative effect on those it affects (see below).
Fire Control (i): while they cannot generate flames like a balor, molydei may nonetheless shape them as they desire. This intensity 13 power lets them amplify, attenuate, or otherwise manipulate fires in their environment (natural or otherwise) at this level.
Growth (a): molydei stand at twelve feet tall, granting them this power at intensity 2. This increases their Strength against normal-sized foes by +2, while applying a -2 to their Agility against the same. Normal-sized foes reverse these modifiers when fighting molydei.
Invisibility (i): though mostly useless against other tanar'ri, molydei can use this intensity 13 ability to great effect against mere mortals and others who cannot see into the infrared spectrum. This power lets them avoid visual detection entirely!
Mesmerism (w): all molydei possess a limited form of mind control, which functions upon their passing an easy difficulty Mesmerism (willpower) action. Those succumbing to this intensity 13 power must comply with any simple command the molydeus issues forth.
Nonapparent Vision (w): at will, a molydeus 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.
Object Animation (i): while many tanar'ri are telekinetic, molydei take this one step further and actually imbue objects in their vicinity, however temporarily, with a semblance of life! They may do this with intensity 13 skill, letting them wield their very surroundings against a foe.
Philosophical Sense (w): another of their useful sensory powers, molydei 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.
Poison (s): the bite of a molydeus' snake head has a transformative effect much like that of various undead. Those bitten by the smaller of the molydeus' two heads will be slain if they fail a challenging difficulty Strength action, only to rise again as a manes.
This will occur even if the victim has no natural predilection towards being sent to the Abyss after their demise. Furthermore, the character's intellect will be reduced to match that of a manes, though they'll distinctly recall their former, lost lives and mental acuity.
If affected, the victim loses one card of Health per day until their death. During this time, any power to cure a poisoning will stop it cold, despite its supernatural nature. Afterwards, only causal control or a miracle can reverse the victim's transformation into a manes.
Revival (s): like the true tanar'ri, molydei can sometimes give death the laugh. Unless killed inside the Abyss or eaten, a molydeus may attempt to reconstitute itself on its home plane with this intensity 5 power. The difficulty involved, of course, depends on how it died.
Sensory Attenuation (w): a specialized form of illusion projection, this ability allows a molydeus to limit the sensory input one can receive - vision, to be precise. Passing an easy difficult Sensory Attenuation (willpower) action convinces the target they are blind for an aura duration.
Summoning (i): in order to further empower them to enforce the Blood War effort, molydei are given the power to summon a select grouping of their fellow tanar'ri - specifically, those who are seemingly designed around it as well, but are generally less powerful.
Once per hour, a molydeus has the ability to summon forth either another molydeus, one or two chasme, or one to four babau. This ability functions with intensity 7 ability, and allows a molydeus to rapidly draw upon a wide array of minions to do its bidding!
Vampirism (i): a dangerous power indeed, molydei have the ability to feed off of the energies of others. They can do this with intensity 10 ability, which allows them to drain like Health from a target with each attack - using it to heal their own lost Health points.
Hindrances / Augmentations:
Monstrous: it should go without saying, but molydei are monstrous entities - just look at them! A molydeus 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 such creatures are simply beneath their notice.
Susceptibility: like all tanar'ri, molydei 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.
Battle Axe (w): when formed, each molydeus manifests an extension of its very life force, in the form of this magical battle axe. They can use this weapon to inflict their Strength +5 in slashing or sorcerous damage - whichever is more effective.
The interesting thing about this axe, however, is that it can attack as if it had a mind of its own - even if its owner is otherwise occupied. This axe may attack using its molydeus owner's Strength score, and may do so anywhere within near missile distance of the molydeus.
If slain, the battle axe of a molydeus will dissipate. The only way to seize such a weapon and retain it is if its owner remains alive. This is an exceedingly risky proposition, for a molydeus will quest without end to get a lost axe back.
Skill / Axes (s): the molydeus constantly use their inherent axes in battle, allowing them to quickly gain martial competency with them. This allows the fiends a reduced difficulty when wielding their special axe - or any other, similar weapon they might be holding.
Idealist: an extreme rarity for tanar'ri, molydei are believers in the cause, and their cause is the Blood War. The process that creates them from the ranks of the true tanar'ri instills them with an overwhelming, single-minded need to further the tanar'ri's ends in the War.
Molydei are single-minded in their pursuit of the Blood War. They're always watching the true tanar'ri for any signs of treachery, no matter how minimal, against their side of the War. While intelligent, their minds are somewhat limited to obsessing over their duties.
A molydeus is a frightening monstrosity. They stand twelve feet tall, and have bright crimson skin. They possess two heads, one being that of a wolf and another being that of a sickly, green-scaled snake. The wolf head can see before the molydeus, while the snake head sees behind it.
The molydei are something of a conundrum. They do not occur naturally, however such a word can apply to the tanar'ri at all. No matter how twisted the suffering a tanar'ri suffers (or inflicts), no matter how powerful it grows on its own, the fiends cannot evolve into a molydeus.
It is theorized that these creatures are true tanar'ri that are molded into their forms by perhaps the Abyssal Lords themselves, though the dark of such is unrevealed to this very day. This theory holds water because even the balors can be taken to task by a molydeus.
Even though the molydei technically serve the balors, while ever watching them all the same.
The molydei act to enforce the Blood War effort. While they discount the actions of any tanar'ri of less power than a 'true' member of their kind (ostensibly because they are beneath notice), molydei monitor the true tanar'ri to ensure that they remain loyal to the cause.
As loyal as any tanar'ri can get, that is. If one of the chaotic fiends wavers in its attentions to the Blood War, or otherwise acts against the tanar'ri interests in such, a molydeus will often be waiting to punish the offender... usually in a most spectacularly lethal fashion.
Which is one reason the nalfeshnee are as subtle as possible in their sabotage of the balors - if they're too obvious, a molydeus or two might show up to put them in the dead book. Hence the generally long-term nature of their plots and intrigues.
* Depending on which version of the Planescape lore you wish to use, the molydei (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.