twisted elementals

Twisted elementals are perversions of their parent elementals. They are often called Inverse Elementals or Undead Elementals.
Twisted elementals are rare. The oldest records of twisted elementals showed them serving as skirmishers in the demon armies of the Second Unmaking. It is unclear whether any arose in the material plane before the Second Unmaking.
Twisted generally appear when events creating a normal elemental occur in areas near the Void or repositories of negative energy prompting some to call them “undead elementals”. Some are called into existence deliberately by spell-casters though this practice is considerably more difficult than conjuring other elementals.
The twisted elemental types are dust, vacuum, salt, and ash. Their physical forms are less protean than common elementals generally appearing much more humanoid. The dark and sinister nature of a twisted elemental is immediately obvious to all onlookers. Twisted Elementals, unlike their healthy counterparts are nearly always hostile to living creatures. Those who believe elementals are sentient beings believe that twisted elementals are in constant pain, causing them to lash out. They are especially hostile against non-corrupted elementals and will nearly always attack uncorrupted elementals in lieu of other enemies, especially uncorrupted elementals of their same base type.
Divine magic affects twisted elementals similar to how it affects undead. Twisted elementals can be harmed by healing magic, rebuked with Necromancy, and turned with Purification but all these rolls are at +2 difficulty for the caster.
Arcane casters can summon twisted elementals if they have dots in Necromancy equal to or greater than the casting level of the Conjuration effect they are using, though the difficulty is still at +3 difficulty compared to summoning or binding a common elemental. Infernalists are believed to have a much easier time summoning twisted elementals.

Twisted earth elementals are commonly called Dust Elementals. While they will attack living beings that get in their way, their preferred targets of wrath are manufactured items and buildings.
Twisted air elementals, or Vacuum Elementals are the rarest and most feared of the twisted elementals. They are creatures of vacuum that still the air around them and suffocate living creatures around them. While not as fast as their non-corrupted brethren, Vacuum elementals can hover and fly and tend to hover at low altitudes so they can suffocate living creatures while exposing themselves to attacks as little as possible.
Twisted water elementals are commonly called Salt Elementals. They draw in moisture from all creatures and things around them. Salt Elementals are probably the most inimical of all elementals towards living beings. While they are attracted to sources of non-tainted water, if possible they will always choose a living target as a source of moisture in lieu of draining a body of water.
Twisted fire elementals are commonly called Ash Elementals. The sputtering embers do not burn those around them, but they act as heat sinks drawing in heat from outside sources to sustain their own guttering flames. Ash elementals will usually prioritize the greatest heat source as their target meaning they can be distracted by fires, but they will proactively defend themselves and attack living creatures in lieu of fire if the ambush or trick is patently obvious.