Fairy Tail: Final Series

Synopsis

Four-hundred years in the past, Acnologia lives as a human doctor in a secluded village that is protected by another dragon named Acnologia, who leaves to investigate rumors of Dragon Slayer magic. Later, the doctor watches in horror as the mutilated guardian returns and leads the other dragons in destroying the village. In the present, the Dragon Slayers' attacks have no effect on Acnologia's spirit due to his immunity to magic. Meanwhile, Lucy devises a plan to trap Acnologia's mindless body within Fairy Sphere, the only spell Acnologia has ever failed to overcome. The other wizards use their magic to lure Acnologia to Hargeon, where they intend to use one of Alvarez's abandoned ships to temporarily impair him with his own motion sickness. Upon arriving, Acnologia senses the threat and instinctively destroys the entire fleet.

(Source: Wikipedia)