That-Called-The-Vlagh is a creature whose more remarkable power is the ability to consciously direct the evolution of its minions, adapting them to the situation as required (the evolution is not instantaneous, but it takes months or even just days, as it is seen in the second book, The Treasured One). Most of Vlagh's creations are vaguely insect-like, venomous and violent, although some creatures have been bred human-like enough to pass as humans (and are used as spies). The creatures also share an Overmind in which all of them know and see what the others do. Despite these major advantages, the Vlagh and the creatures of the Vlagh are not intelligent. They can't even understand the meaning of death which causes many defeats early on but as they fight more they begin to avoid simple traps like arrows and poisoned spikes that the protagonists use.
The Vlagh's origins are unknown. It is possible it predated even the Elder Gods.