(evil, extraplanar, lawful)
Source: Tower of the Last Baron, pg(s). 30–31
It is speculated that Asmodeus spawned the first crepitus, sometimes called magewretches, to tempt and corrupt mortal wizards into damning their souls. Yet while it is true that the crepitus is a highly intelligent creature with a gift for spellcraft and all things arcane, its great intellect is countered by its foolishness and inability to competently lure mortals to Asmodeus's will. As a result, specimens seen on the Material Plane are more often slaves than fiendish tempters.
A crepitus stands 3 to 4 feet tall, with bright eyes in a saurian head that appears too large for its gaunt, rune-covered body. Its shoulders sprout bat-like wings that allow it to fly with ease, and its sharp talons are surprisingly nimble and capable of fine adjustments when conducting magical rituals. A typical crepitus weighs 30 pounds. Like other fiends, crepiti don't require food, but they take particular joy in consuming wizards' familiars (and sometimes the wizards themselves). Crepituses are native to Hell, and many lurk around Asmodeus's infernal palace, often serving as messengers.
Habitat and society
Left to their own devices, crepitus devils are cunning, malicious pranksters, content to while away their days flitting about Hell and tormenting lost souls and devils alike. Yet crepituses are rarely left alone for long, and it is likely from this fact that their long-standing racial hatred of wizards stems. Highly valued for their spell-like abilities and intuitive knowledge of magic, crepituses are frequently bound into contracts or enslaved outright by mortal wizards and other fiends, a situation the intelligent devils find extremely demeaning. This situation is not helped by the fact that crepituses are frequently the first gifts handed out by higher-ranking devils attempting to seduce mortal magic users.
If given an opportunity, a crepitus goes well out of its way to destroy wizards and burn their precious spellbooks to ashes (not necessarily in that order). Chelish wizards regularly bind crepitus devils as servants, and view having an enslaved crepitus as a mark of prestige. Crepituses enjoy lording their power over their significantly weaker imp cousins, and referring to a crepitus as an imp is the gravest possible insult.
The crepitus is a frustrating creature for scholars of the infernal to deal with and the source of significant debate. Included in some of the earliest treatises on the Pit, these imp-like fiends found their way into infernal bestiaries, tomes of dubious diablere, and even saw occasional summoning and interviewing by misinformed diabolist. Yet, crepituses are no more devils than hell hounds, cerberi, hell gigas, asuras, velstracs, or any other of the terrifying creatures that often make their lairs amid the flames of Hell.
Certainly, the confusion has to do with the wings, red skin, natural maliciousness, and so many of the other traits that link these nasty fiends to imps, especially their interest in corrupting souls and serving mages, but such does not a true devil make. For all their similarities, they lack the powers and abilities inherent in those of true infernal pedigree—the immunities, traits, and ability to call on one another that typify actual devils. Their tendencies for pranks and wanton destruction also suggests a mind lacking the discipline of a true diabolical mind.
Thus, while certainly similar and seemingly interested in passing themselves off as devils, for all these fiends' submission and service they will always be mere suppliants in the face of true devilkind, ignored, manipulated, abused, or used as the lords of Hell see fit.