Memento

Memento (破り輪廻 (メメント) Memento; "Defying Saṃsāra") is a Caster-type Magic, and a form of Seith Magic (セイズ魔法, Seizu Mahō). It is also considered form of Reincarnation Magic (転生, Tensei Mahō), as it manipulates the user's own soul directly, as opposed to simply ambient souls.

Usage
Memento is a relatively rare magic that allows the user to manipulate their own soul for one express purpose — living forever. Through Memento, the user is capable of expelling their soul from their body, and in doing so, destroying their body entirely. While the body can normally exist without the soul, forcible removal of something so normally ingrained with the body causes a reaction the causes it to degrade, turning into dust. With their soul free and unencumbered by the chains of a physical body, the user of Memento is forced to find a new body. Once they have found a suitable 'host', the user must possess the body. In doing so, should they prove to have a strong enough will, the soul already within the body is mentally subdued and repressed, allowing the user of Memento to move the new body as if it was their own. Should the user's own will not be sufficient, they will be rejected from the current host, and be forced to begin their search for an applicable body once more.

Despite the horrific usage of this magic, it is not considered a form of Forbidden Magic Forbidden Magic (禁魔法 Kinmahō), due to the fact that the technique is relatively unknown, and the Magic Council itself remains blissfully unaware of the magic.

Trivia

 * Memento comes from the phrase, which is is the medieval shorthand for the Latin proverb "memento moriendum esse", meaning "remember you will die".
 * Memento shares a similar name to the curse,, but has a distinctively different effect.