The Pre-Emptive Materia, when equipped to a character, raises the chances that party finds itself in favourable battle conditions upon the start of battle, where the enemies all have their backs to the player's characters, or the player finds their characters surrounding their enemy in a "pincer" attack. This materia's effect can stack with another Pre-Emptive Materia up to a maximum chance of +85/256 (+33.21%) for a 'Pre-emptive Attack!'. When this materia is Mastered, it can also decrease the chance of Ambushes and Back Attacks by 50%. This will only work if you place the Pre-Emptive Materia on your third character (the one on the bottom of the screen). In addition, whenever you change materia or equipment on a character that doesn't have a Pre-Emptive Materia equipped, un-equip and then re-equip the Pre-Emptive Materia on your third character again so that the game properly fixes the check for this bonus.
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