Most of the information given here is taken from the VS Battles wiki so please give the members of the VS Battles wiki (especially the Admins) the credit they most definitely deserve.
Omniscience is the state of having all knowledge, or in other words, knowing everything. A character that is omniscient knows everything that their opponent is going to do before they do it, and exactly what to do to win any fight. An omniscient character is still capable of being overpowered and losing, however. Also knowledge of other fictions is not a requirement for omniscience, so a character that knows everything about their own fictional franchise is considered to be omniscient.
There is a distinction between this power:
- Absolute Omniscience - Actually knowing anything and everything that can be known. They know every answer to every question and know what happened, what happens and what will happen. By knowing something, one can also understand every counter available for that certain something, thus being unable to be defeated by said subject in most cases.
- Inherent Omniscience - The ability to know anything that one chooses to know and can be known. The power may or may not allow the user to have all information at all times as some knowledge may be spontaneous while some may require the action of others. To an extent this can also be called "Nigh-Omniscience", which allows a character or entity to know almost everything about their fictional continuity, with the exception of a small amount of information (usually what an even more powerful character wishes to conceal from them).