Quadra Magic (まほうみだれうち, Mahō Midareuchi?) is a support ability in Final Fantasy VII that allows for casting the linked Magic or Summon Materia four times in succession with the MP cost of a single spell, but has its damage cut in half. This can be countered with the materia MP Turbo. In this sense, it is similar to the Barrage ability featured in other titles, only magical in nature. Quadra Magic doesn't work with Knights of the Round, and if the party casts Escape with Quadra Magic, it will only be cast once. However, it may also be equipped to Master Summon to counter the single cast of KR. (Note it can also be linked to Master Magic). Quadra Magic can be found in a Materia Cave north of Mideel that can be reached with a river, mountain or sea chocobo. It can also be reached through the Highwind through means of a glitch.
The spell used with Quadra Magic picks a random target out of the chosen party (enemies or allies) and attempts to unleash all four castings on the same target. If the target dies before all four castings are used the sequence stops and all unused castings are lost. Area-of-effect spells simply hit the chosen party four times. Each casting has its damage cut in half including attacks whose damage is based on max HP, like Demi and Full Cure. Statuss that don't have a 100% chance of hitting also have their accuracy cut in half.
It is possible to link multiple Quadra Magic to the same Materia, which will cause the spell to hit an extra time per equipped Materia. E.g. having three Quadra Magics attached to three Fire Materia would cause Fire to cast six times. The maximum is eight spells in succession, if one uses five or more Quadra Magic Materia at once. It is also possible to quadruple the magic used as a counter-effect: Linking a Materia with both Quadra Magic and Magic Counter/Final Attack/Sneak Attack, when the casting is automatically triggered, the spell is cast four times.
If the first spell is reflected, the rest of the spells hit the target the spell was reflected to instead of being reflected again. When cast with the W-Magic Command Materia, the spell is quadrupled both times, meaning the character can cast a spell eight times in succession, or a whopping 16 times in succession if equipping five Quadra Magic Materia at once.
There is a glitch involving using Quadra Magic with Ultima while another Ultima Materia is linked to either HP or MP Absrob. With this setup, the game may freeze when Ultima is cast against bosses that have multiple limbs.