Witches manifest when a female Wishborn's Soul Gem becomes corrupted beyond the ability to be cleansed. The girl then becomes the Witch, which takes on a psychological representation of a combination of the Wishborn's desires and despair, forging both into a nightmare of eternal hopelessness and grief. A Witch conceals her presence behind a barrier at any given location in the world, which is not visible to anyone but Wishborn eyes.
Only female Wishborn may become Witches, due to genetic differences in how the corruption affects them and their physical manifestations. The male forms of this corruption are known as Yoma. The strength and overall power of a Witch can often be determined by their physical appearance, once confronted in the labyrinth; stronger Witches are able to retain more of their sanity than their weaker once-allies, and as such, will appear closer to their original selves. Witches are known for their mind games and tend to take a toll on the mental and emotional health of those who combat them, often drawing into account weaknesses, shortcomings, and other problems that the Witch is inclined to fault them for. Contrary to Yoma, Witches cannot always be destroyed with brute force; occasionally one must match wit for wit, and find a specific method of ousting the Witch, usually related to what the Witch in question represents.
From her hiding spot, a Witch extends her grief and despair through mental auras that are capable of transfixing and luring those with weak minds and hearts to act out their negative emotions, often through murder and suicide. Those who become hypnotized in this way are only partially aware of what they are doing, and when confronted will often reinforce their belief that they are doing the right thing for themselves and others, perhaps that they no longer have any hope otherwise.
Witches tend to be more or less powerful depending on the strength of the Wishborn before corruption; those who fought tooth and nail to the bitter end tend to make much more potent adversaries in Witch form than those who succumb with little effort.
A Witch hides within the core of a labyrinth that lies inside the barrier she creates, and a Wishborn must traverse this maze in order to confront and hopefully defeat the Witch in question. The strength of a Witch lies in the fact that they are not only undetectable by non-Wishborn, but they are not susceptible to damage or attack from them, either. Only those transformed Wishborn may enter a labyrinth, as well as assault a Witch and expect to have any success. A Witch may have underlings, known as familiars, that will likely assault the Wishborn during their hunt for the Witch, and while nowhere near as powerful as their mistress, they have the ability to become Witches themselves if left alone or idle for long enough. Once a Witch is defeated, those still under spell have their thoughts fully returned to them, and often exhibit remorse and guilt for what they had done or were about to do.