Nonexistence.
The ability to completely erase any kind of existence. A specialized variation of Omnipotence.
This ability allows the user to annihilate anything and everything, physical, spiritual, conceptual, metaphysical, present, past, future, probable, possible, abilities themselves, with no protection nor exception of any kind.
When used superficially, some trace of the still target remains, allowing for a possible restoration via event erasure. External restoration may even be possible, if the erasure is superficial enough.
When used at full power, targets are completely wiped out on every level, to the point where they never ever existed, and are totally impossible to recreate by any means, no matter how great.
Needless to say, the user is universally dreaded as the embodiment of the Primal Fear - and with good reason.
Damn, that's rather good and slightly scary at the same time...