Soft Places

Where the Underhollows have been subjected to corruption by unwholesome energies, the fabric of the material plane can grow thin. This creates soft places, where the material World lies close to the planes below. This allows more polluting energy to pass into the Underhollows, eventually weakening the boundary until a portal is created. The nature of the pollution determines the effects on the area, as well as the form of any portal that forms.  

Miasmal Grottos

An imbalance of Necrosis creates the environments called Miasmal Grottos, dark realms of undeath and sepulchral chill, where gateways to the Grim Plan can form.   Although deep beneath the surface and away from Soraes' light, the Underhollows are rarely cold. This is not true of the miasmal grottos, where a bone-deep grave chill permeates the air, stone and ecosystem. Cold mists limit visibility and sap the vitality of the living, sickly darklight ferns and lichens eke out a poor existence, and few animals save pale, blind rats live there. Instead these regions are occupied by Uncreated Undead, physical or ethereal, all gripped by a craving for the blood, flesh, breath or lifeforce of any living creature.   When gateways to the Grim Plain open, darker and more deliberate creatives may enter and begin to organise the resident undead. These miasmal domains are a serious danger to the other residents of the Underhollows, and either draw an aggressive response or, left unchecked, will attempt to spread their influence.  

Abyssmal Deeps

An imbalance of revenant and fluvial energies degrades the separation between the material and The Abyss, creating the fiend-haunted landscapes of the Abyssmal Deeps.   The abyssmal deeps are a moveable feast, their nature based on the abyssal realm which they are close to. Most are drawn to Escharon, the great chasm, and become cold and windy; the Abyssal influence takes particular hold in the local spiders, which frequently become poss­essed by the spawn of Liloth, and bats, who instead are invested with the infernal power of the Fathomless Vertex.   Eventually, fiends may manage to break through from the Abyss, bringing their conflict to the Underhollows. Abyssal Rifts of this sort are invaluable to the fiends as a point of entry into the material. As a result, they are fiercely defended against both the residents of the Under hollows, and rival factions in the Deep War.  

Unfathomable Vaults

Concentrations of ifril, usually related to the presence of colossal remains, cause terrible distortions of reality known as Unfathomable Vaults. In theory, these could develop portals to the Void, but as such they are always a priority for the custodians of the Underhollow to either eliminate or seal off, and rarely develop so far.   The nature of the world in such places is dangerously altered. The energies here warp both space and time; twisting gravity, reversing causation, shattering reality into fragments and reassembling it at random. While horrifying in and of themselves, and often occupied by terrifying and disturbing outerfolk, these regions of fractured existence are merely a labyrinth which forms as a defensive layer around a dead or dormant Colossus.   The labyrinths around these vaults are occupied by svarts, neogi and other outerfolk, as well as beyonderbeasts and extra-ontological monsters of various kinds, many of which are otherwise unknown on Aiaos. Further in, mind flayer nests and beholder nightmarescapes form from the maelstrom, while at the centre the colossus whose presence causes the disturbance seeks to heal and return to awareness.   The denizens of the Underhollows, and especially the ash elves, holder dwarfs and jaskinisse, watch for emergent Vaults and take steps to either purge them when they are small or, more often, seal them away behind great seals and the deep bindings, transforming the fortress of the labyrinth into a prison. These sealing magics are ancient, and many are only half recalled in old sources, since few new Colossi have come to Aiaos in generations.