Acausality

Disclaimer
This information is taken from the VS Battles Wikia site. So please give the members of the VS Battles wiki (especially the Admins) the credit they most definitely deserve.

Summary
Acausality is defined as the ability to exist outside of causality, or the natural flow of manipulation defined by cause and effect. An entity that is acausal has no true beginning or end, and is thus basically immune to offensive causality manipulation and time travel. Even if you go back in time and kill an acausal being in the past or prevent him/her/it from being born/created, it will still exist in the present and other timelines. Often, even if an acausal being is killed in the present it can still survive by appearing from another timeline. Thus, acausal beings are very difficult to permanently destroy, often requiring the use of high-level Reality Warping.