9. Makarov Vs Hades - Fairy Tail
While Makarov Dreyar - the seemingly all powerful master of the Fairy Tail mercenary guild - had been bested before, the first time was more a result of his opponent outsmarting him. Once Makarov and Jose actually went blow to blow, Jose barely lasted five minutes.
No, the moment where Fairy Tail fans were shown the true limits of the seemingly invincible master was when he went up against his oldest friend, Hades.
Hades, now the master of the Dark Guild Grimoire Heart, came to Tenrou Island - where the strongest mages of Fairy Tail gather to compete for a single promotion - to eliminate the strongest of his enemies in one fell swoop. Master Makarov, quickly figuring out what's going on, goes to confront Hades immediately.
And he loses. Hard.
Oh Makarov fights the whole way, tooth and claw, even whipping out his end all, be all spell - Fairy Law. But Hades has something that the previous villains didn't: years and years of experience working directly with Makarov. He quickly circumvents all of his attacks, shrugs off Fairy Law, and takes out the greatest of Fairy Tail's mages within the span of a single episode. All without breaking a sweat.
It should come as no surprise that the heroes' eventual victory over Hades comes off more like luck than anything else. Because this fight showed above all else, that Hades is not a man you mess with.