The Unaware Sword Saint Who Trained for 100 Million Years: Overwhelming Another World with the All-Purpose Divine Artifact Mocked as a Mere Stick and the "Sword Demon" Persona Born from Extreme Training

A High school boy by the name of Ichitaro Yamada has always had one defining trait: Once he gets absorbed in something, he never stops. One day, his entire class is summoned to another world as heroes. But when their hero ranks are revealed, Ichitaro receives the worst rank of all. Branded as useless and unwanted, he is thrown into a prison where time itself has stopped. Instead of giving up, Ichitaro does the only thing he can: train. For 100 million years, he sharpens his body, mind, and swordsmanship until he masters every style imaginable. By the time he finally leaves the prison, the boy once mocked as the weakest has become an overwhelming sword saint capable of dominating another world.