Mind Eater

Ruby: Mind Eater is a spell is used to control people. The person on whom the spell has been cast cannot break the spell by themself, so another person would have to break the spell for them. The only known people who can apply the spell are Konoe A. Mercury, Hazama, and Hades Izanami.

Information
The spell is first seen when Nine uses it against Yūki Terumi once he has fused with Kazuma Kuvaru; the spell effectively turned Terumi into nothing more than a sleeping slave but because the spell can only affect one mind, Kazuma took over his body and became the Terumi that was known in the Dark War. Kazuma then came to Trinity Glassfille and threatened to kill Nine if the spell wasn't lifted; she obeyed and lifted Mind Eater. Trinity was swiftly disposed of by Terumi, now in control once more.

Nearly a century later, the same spell was used on Tsubaki Yayoi after she went blind from her overuse of the Sealed Weapon Izayoi. After the spell had set its toll on her and forced her to fight her lifelong friends, Noel Vermillion and Makoto Nanaya, the Sealed Weapon took on its true form and broke the spell, turning Tsubaki into Izayoi. Afterwards, when Tsubaki turned back into a normal state, the spell remained broken.

Jin Kisaragi described it as an curse, in which the user projects it's own cognizance atop the target's conscience. Like a dark "shadow" that looms in the target's mind.

It is unclear to where the memories absorbed by the Mind Eater go. Hazama points out to the ends of the Boundary, as one of the possible destinations, while Litchi questions if those aren't sent to a particular Boundary. In reality, Hazama was feigning ignorance, as he not only knows to where those go, but also can draw them out and use them to his advantage. An example of it is how he broke down Ragna's little sister, by showing Saya her own memories, with great detail and recreated sensations.

Notable victims

 * Yūki Terumi (during the First War of Ars Magus; set free by Trinity Glassfille)
 * Tsubaki Yayoi (during the course of BlazBlue: Chronophantasma, set free by the Sealed Weapon Izayoi when it took on its true form.)
 * Konoe A. Mercury (during the course of BlazBlue: Continuum Shift and BlazBlue: Chronophantasma)