Koko wa Ore ni Makasete Saki ni Ike to Itte kara 10-nen ga Tattara Densetsu ni Natteita.

When demonic forces surround the hero’s party, mage Luck orders his companions to flee and stays behind to hold the enemy alone, expecting it to be his final battle. Instead, he fights without sleep or rest until the enemy commander finally falls ten years later. Returning home, Luck discovers that the world remembers him as a legendary hero who sacrificed his life, while his own body has somehow regressed to that of a teenager.

Unwilling to disrupt his friends’ lives or live beneath the weight of his fame, he hides his identity as “Lock” and registers as a low-rank novice adventurer. All he wants is peace, but ten years of impossible combat make pretending to be a beginner far harder than expected.