FF7 Beginner's Hall(Limit Troop) - LN1's Words

-Developing Limits
Using a Limit Break enough times will unlock the next. To unlock the next level's first Limit Break the character must kill a certain amount of enemies.
-Extreme Limits
Some mythical ultimate Limit Breaks that are special or something. Since it's am in-game rumor in a Square RPG, you know there must be something to it.