User blog comment:Water Dragon Slayer/DREAM BATTLE CHRONICLES: SECOND MATCH!/@comment-11966702-20130726045815/@comment-7418318-20130727075839

I just wanted to point out that most likely Mavis would use Fairy Glitter against a single oponent, rather than Fairy Law, since it seems more suited for single combat.

With Fairy Law going through walls an everything I'd imagine the two spells wouldn't interact resulting in Zeref and Mavis hitting each other.

Between Hades being instantly killed by the death pillar (allthough he was already very badly hurt, so no assurance here) and Jose surviving Makarov's Fairy Law such a double hit would most likely result in Mavis losing.

With Fairy Glitter the spells might crash into each other, cause a massive explosion and send both combatants flying backwards.