[quote=thewizardguy]
Gildarts. Destroys anything he touches, capable of wiping out entire islands. Makarov, using Fairy Law, can wipe out anything that isn't an ally. Gajeel, Erza, and Gray will all be preventing you from killing Natsu, which you need to do in order to gain his powers. Furthermore, it's quite likely that the other Guilds would help out Fairy Tail, meaning you might even get to fight more Saint-Mages.
[/quote]

swarm... as in metric fucktons... none of those four are able to break through their carapace. makarov takes an ungodly amount of time to charge up fairy law, and gildarts can't kill them all before they kill him. and by the time the other guilds come fairy tale and the surrounding town would be infested