Reduces the enemy's Magic.Description
Magic Break attempts to lower the enemy's Magic by 25% per use. It has a 50% base accuracy, but successive uses on the same enemy stack, greatly weakening the foe. It works on any enemy and the effect cannot be dispelled once inflicted, as the effect is a stat reduction rather than a status effect.
Magic Break weakens an enemy's magic attacks. Though the stat reduction is formidable, Break moves' downside is that Steiner is one of the party's strongest damage-dealers, and Magic Break would use his turn for something other than offense, and it may miss. The player could instead protect their party with Shell or resist elemental damage, as a lot of magic is elemental. It also has no effect on damage from fractional damage spells.
In battles where the player is "idling" while waiting for Zidane to steal all goods on offer, Steiner's Break moves may come to use: they weaken the enemy, but do not kill it off.
Behind the scenes
Magic Break originates from the Rend-type abilities used by Knights from Final Fantasy Tactics, though one that disables the target's Magick Power does not feature due to the ability destroying equipment; Rend Magick instead attacks the target's MP. After appearing in Final Fantasy IX, the Break abilities went on to appear as much more useful abilities in Final Fantasy X and Final Fantasy XII. The debuffs in Final Fantasy XIII could also be seen as being in the same continuation.