Fairy Law

Fairy Law (lit.Law of Fairies) is a Caster Type spell utilized by Makarov and his grandson        Laxus Dreyar. It is considered a very powerful magic and is one of the rare legendary spells. When activated, a bright light envelops the area and inflicts heavy damage on whoever the caster perceives from their heart as an enemy, leaving friends and bystanders completely unharmed. The choice between friend or foe is decided by the user's spirit, and he can not lie to this magic. Fairy Law is also one of the three great Fairy magics.

The spell's strength was so great that it defeated Jose, a Wizard Saint, in a single blow. It is implied that this spell is Makarov's ultimate magic. According to the second master of Fairy Tail, Master Purehito, Fairy Law is deterrent magic and is meant to discourage further action from enemies, and is not something that should be released whenever the caster feels like it.

Hades used same spell with Fairy Law except his color and name. Grimoire Law is an evil variation of which is utilized by Hades (formerly Purehito). If used against Fairy Law, it would cause horrible devastation.