Before I delve into the oinoloth, I want to settle an issue regarding yugoloths—or at least, regarding my interpretation of yugoloths. The issue involves the question of what plane yugoloths are native to, and specifically, whether they can be killed (as opposed to just destroyed) on any plane other than Gehenna, the outer plane of “lawful evil neutrals.” My take, which differs from pure canon, is that yugoloths may be numerous in Gehenna, and some yugoloths may be native to that plane, but Hades has as strong a claim on them, if not stronger.
The fifth-edition Monster Manual says:
Back to Gehenna. When a yugoloth dies, it dissolves into a pool of ichor and reforms at full strength on the Bleak Eternity of Gehenna. Only on its native plane can a yugoloth be destroyed permanently. A yugoloth knows this and acts accordingly. When summoned to other planes, a yugoloth fights without concern for its own well-being. On Gehenna, it is more apt to retreat or plead for mercy if its demise seems imminent.
This paragraph isn’t as ironclad a statement that yugoloths are native to Gehenna, and only to Gehenna, as one might think. First, it doesn’t state explicitly what a yugoloth’s native plane is, only that if it’s killed somewhere other than its native plane, it re-forms in Gehenna. Another paragraph on the same page states, “Yugoloths are fickle fiends that inhabit the planes of Acheron, Gehenna, Hades, and Carceri” (the last of these, in AD&D, originally called “Tarterus,” a misspelling of “Tartarus”), implying that any of these planes could be a yugoloth’s native plane. Second, I reserve the right to declare occasionally that the Monster Manual flavor text is full of it, as in the case of the soldierly hobgoblin that for some reason instantly forgets all its training and abandons all its discipline if it happens to catch a glimpse of an elf, or the use of “efreeti” as a singular noun rather than “efreet.”
Before yugoloths were yugoloths, they were “daemons,” the neutral evil counterpart to lawful evil devils and chaotic evil demons. The first daemons to appear in a D&D sourcebook were the guardian daemon, mezzodaemon and nycadaemon in the Fiend Folio (the last two are now the mezzoloth and nycaloth). The guardian daemon’s home plane is unspecified, but the mezzodaemon and nycadaemon are described as inhabiting “the Lower Planes between the Abyssal Layers and the Hells—i.e., Tarterus, Hades, Gehenna” (idiosyncratic italics in original). Gehenna doesn’t even appear first in that list. Continue reading I Don’t Feel Like Arguing About Yugoloths