Valden

The Valden (singular Vald) are spellcasters that have imbibed aberrant blood (that of beholders, aboleths or nothics especially). The victim's soul is corroded away and the body bends and twists unnaturally, gaining supernatural strength, unearthly magic, and an unbreakable (though vitriolic) servitude to their master--this being the aberration whose blood was consumed.
A Vald appears vaguely humanoid, with disproportionately muscular limbs beneath a leathery black hide. A Vald's head has a mouth, but no eyes. Instead, the creature sees from half a dozen eyes peering out from tears in its unnatural flesh.
The origin of Valden is a grim and amoral one; aberrant blood is a key component for Potions of Invulnerability, but only after distillation in a living, humanoid host. The Valden are both slaves to aberrant masters, and the dark workings of the most immoral alchemists alive.

Behaviour & Ecology

The Valden do only as ordered by their master. If their master is dead or lost to them, they invariably collapse dead from withdrawal within a few days. In the interim they remain unpredictable, and either fall into a tragic state of apathy or stirring to a violent frenzy until withdrawal withers their bodies to nothing.
As the Valden age, their black skin weathers and dries to a harden, plate-like material that's virtually impenetrable.

Hunter & Gatherer Notes

The Vald can only be killed in one of two ways. Either withdrawal of the aberrant blood which sustains them, or by gouging out each of its eyes with a weapon of Meteoric Iron (Starmetal). Otherwise, the Vald can regenerate in a matter of hours or days.