Maurezhi

From Mordenkainen's Tome of Foes (2018):

When Doresain, the King of Ghouls, corrupted a society of elves, he created a new breed of demons to lead packs of ghouls and ghasts in the material world.

Horrid Infiltrators. When a maurezhi consumes the corpse of a humanoid it has slain — a process that takes about 10 minutes — it instantly assumes the creature’s appearance as it was in life. The new appearance begins to rot away over the next few days, eventually revealing the demon’s original form.

A Plague of Ghouls. Maurezhi are contagion incarnate. Their bite attacks can drain a victim’s sense of self. If this affliction is allowed to go far enough, the victim is infected with an unholy hunger for flesh that overpowers their personality and transforms them into a ghoul.

From Planescape: Monstrous Compendium Appendix II (1995):

The maurezhi are a plague in the worlds beyond the Abyss, a scourge of evil that taints any plane it seeps onto. Maurezhi prey on mortals, spreading chaos and evil through their fearsome appetites. Like the nabassu, maurezhi gain strength with each mortal they devour — but instead of absorbing mortal life forces, the maurezhi feed upon corpses, stealing portions of their victims’ memories, skills, and appearance.

Maurezhi seek opportunities to slay and devour mortals wherever they can find ’em. Most maurezhi’re doomed to serve as marauders and skirmishers in the Blood War, but a few find ways to escape onto the Outlands or the Prime and begin a career of bloody murders and vile feasts.

Maurezhi leap and caper in sudden, unpredictable movements when excited or angered. They can communicate by means of telepathy, but the only sounds their rattling bone-boxes can make’re gibbering howls, grunts, and shrieks.

Maurezhi live only to consume the most powerful and intelligent mortals they can find. They’re especially fond of waylaying lone travelers or adventurers, consuming them, and then assuming their appearance and using their acquaintances to seek out another victim while concealing the disappearance of the previous one. Between suitable victims, maurezhi’re fond of haunting graveyards and barrows, sating their taste for the flesh of mortals.

Most maurezhi aren’t given much of a chance to begin their growth in this fashion, though. They’re frequently recruited by the babaus or hezrous and sent to fight in the Blood War. In the Abyss, a typical maurezhi’s never had the chance to consume a human. However, a small percentage of maurezhi encountered in the Abyss will be full-grown creatures that’ve completed their expedition and returned to the Abyss at the peak of their power. These tanar’ri function as assassins and spies, roaming the Lower Planes to keep an eye on the baatezu war efforts.

The DM can decide what kinds of sods the maurezhi’s already consumed and what they may or may not have known. Whenever possible, maurezhi seek out and consume mortals of exceptional skill and power. Each previous victim can be determined using the chart below:

d%:              Victim:

01-40:

• 0-level character (possible proficiencies, identity, or information gained by the maurezhi)

41-65:

• Warrior of level 1-8 (possible improved THAC0, weapon specialization, tracking, or ranger skills)

66-70:

• Wizard of level 1-6

71-80:

• Priest of level 1-8

81-95:

• Thief of level 1-10 (with appropriate thief abilities)

96-00:

• Bard of leyel 1-8 (with appropriate thief and non-magical bard abilities)

A maurezhi begins with average Intelligence, but each victim it consumes adds 1-2 points to its basic Intelligence rating if the victim was more intelligent than the maurezhi. As noted before, the memories and skills of each of their victims are available to the maurezhi, and it’s possible for the fiend to have very unusual or rare secrets in its head.

Although maurezhi devour all kinds of carrion and corpses on a daily basis, this doesn’t increase their power. To consume a corpse, the maurezhi must personally kill the victim and devour him or her within one turn (10 minutes) of the murder. The grisly process requires no less than half an hour, and if the fiends interrupted, it can’t completely consume its prey. A character who’s been thus consumed can’t he raised or resurrected, and can be returned to life only with a very carefully worded wish.