Corruptura

Corrupturas are creatures that can be spit from the mouth of a Vladat and attach themselves to the head of another being, allowing the Vladat to control the being's actions.

Since the Corruptura appears to provide a link between the mind of the victim and the Vladat, it's not clear whether the Corrupturas themselves even represent a symbiotic species or merely an aspect of the Vladats' biology, possibly an anatomically-independent organ.

Biology
The Corrupturas are diamond-shaped creatures with one eye, small horns, and bat-like wings.

Abilities
When spat out by a Vladat, a Corruptura affixes itself on the forehead of a being, thus giving the Vladat control of that being. The victim is still conscious and aware of his/her actions, but have no control over his/her physical body. Basically the victim becomes an unwilling puppet.

Another property is the fact that the Vladat can control multiple beings at once, with Lord Transyl being able to control the majority of Anur Transyl's population and Whampire taking command of Zs'Skar's three henchmen.

Weaknesses
Corrupturas are useless against a species that can make themselves intangible, such as an Ectonurite. This weakness is not a problem if they remain tangible.

Corrupturas cannot mind-control a species with slippery skin, such as Hobble's Species.

Corrupturas are ineffective on cybernetically-enhanced beings such as Exo-Skull.