Environment any (Abyss)
Organization solitary
Treasure double

The most terrible of the qlippoth, with the exception of the qlippoth lords, is doubtless the immense iathavos. Believed by many to be a singular entity, a unique qlippoth so abhorrent that even the Abyss cannot bear to allow more than one to exist at any one time, the iathavos is often encountered attended by numerous nyogoth qlippoth that squirm over its body or under its bulk, feeding upon the wastes and fragments left behind by its shuddersome passing. These nyogoths are invariably other creatures that the iathavos has absorbed and remade—they represent one of the most heinous fates that could await would-be explorers of the deepest Abyssal rifts.

The iathavos crusades against the demonic scourge, but the monster does not limit its attentions to seeking out and destroying demons in preparation for the return of the Abyss to qlippoth rule. Indeed, the iathavos has the ability to shift among the various planes of the multiverse, and often travels to Material Plane worlds to systematically scour realms clean of mortal life, thus ensuring that these worlds can no longer provide the raw materials—sinful mortal souls—the Abyss relies upon to create new demons. Worlds visited by the iathavos are notable for the widespread devastation and the unusually large populations of nyogoths that remain behind to consume every last speck of decay the iathavos leaves behind.

The iathavos can be called via the most powerful spells, such as gate, but its immunity to mind-affecting effects and its vast size ensure that only the most desperate or most insane ever attempt such a self-destructive act. In all known cases, the deliberate conjuration of the iathavos to another world has done little more than draw the attention of the powerful creature to that world, so that even if it is banished back to the Abyss before it can cause too much devastation, the iathavos remembers the visit. It often returns under its own power at a later date to pursue its own goals on the newly discovered world. Only if the iathavos is presented with defenders that prevent it from achieving its destructive ruin does it flee back to the Abyss via plane shift—in such cases, the qlippoth often waits for centuries or even millennia before returning to that world, for there are always easier realms to destroy.

The iathavos is a powerful and horrifying monster made all the more devastating by its incredible intellect. The creature takes care to plan its major assaults on demonic enclaves or mortal cities, even though it is powerful enough that few creatures in the multiverse can give it pause. When the iathavos is slain, the multiverse typically has only a relatively short time before the Abyss births a replacement monstrosity for the defeated qlippoth. This newly born iathavos is an entirely new creature—it does not share the memories of the previous incarnation, nor does it possess any advanced hit dice or class levels the previous monster may have gained, yet its appetite and hatred for demonic life and the sins that create such life remain constant and unending.

To call such an iathavos a “newborn” is somewhat misleading. Although technically a freshly created creature, newborn iathavoses do not undergo a “childhood.” They form fully grown, as presented here. Yet with each new incarnation of the qlippoth monstrosity, changes can occur. A new iathavos might have slightly different spell-like abilities, for example, or the nature of its horrific appearance might change from that presented here. As an iathavos continues to hunt and destroy, it grows more powerful—an advanced iathavos typically gains more racial Hit Dice as a result. An iathavos that gains power by taking class levels is not unheard of, but it is quite rare—most who do take levels in sorcerer.