The Last Mercy

They all turned as Su Yan—still partially draconic—landed near them. By that point, the rest of Grimoire Heart had been driven to the shore, forced back onto their airship. Su Yan allowed them to reclaim Zeref's unconscious form—on one condition. Ultear reversed the Tenrou Tree's damage and set the island to rights.

Though confused and fearful, Grimoire Heart's members obeyed. Soon, their battered airship took flight, spiriting them and Zeref away from Tenrou Island.

"Kid," Hades muttered as he was dragged aboard. "You're unbelievably naive, letting us go after everything we did."

Makarov's hands clenched. "You once taught me much, Precht. Consider my letting you go as… thanks for the past. But if you dare try harming Fairy Tail again, we will finish you."

Glancing back at Su Yan's towering silhouette, Hades felt a shiver of dread. He still carried hopes of a "Great Magic World," pinned on Zeref. But he knew too well that if he ever crossed Fairy Tail again, Su Yan might not spare him a second time.

As the Grimoire Heart airship vanished over the horizon, Fairy Tail wizards clustered around Su Yan. They'd expected him to wipe out every last one of their enemies, given how mercilessly he fought before.

"Su Yan," Makarov began. "I truly thought… well, that you'd—"

Su Yan shook his head, returning to human form. "This is the final mercy I'll grant them. Let them walk away with their illusions. Next time we meet, I'll destroy them all—no more mercy."

Fairy Tail members exchanged glances, a mix of relief and respect in their eyes. Because while they knew Su Yan's ruthless streak, they also knew he was not a monster. On Tenrou Island, that day, everyone understood that the greatest strength was born not from cruelty or "abyss," but from the fierce desire to protect what one loves.