Raised on the isolated Monster Isle, the human orphan Dai dreams of becoming a true hero, a goal nurtured by his adoptive monster grandfather, Brass, and the slime Goro. His peaceful life shatters when the fake hero Avan arrives to train him, revealing that the Dark Lord Hadlar has resurrected. To combat this looming evil, Avan sacrifices his life using the explosive Megante spell against Hadlar. Grief-stricken and awakened to his hidden dragon powers—manifested as a glowing dragon crest on his forehead—Dai sets out into the wider world alongside his cowardly companion, Popp, a former wizard-in-training.Joined by Maam, a martial artist wielding a magical gun, the trio forms the "Disciples of Avan" to defeat Hadlar and his master, the Dark King Vearn. Along their perilous journey, the group expands. They recruit Crocodine, a beast king redeemed by Dai’s unwavering valor, and Hyunckel, a tragic swordsman raised by Hadlar who initially seeks revenge against Avan. Hyunckel eventually joins their cause, wielding his mentor’s dark sword techniques for good.As the war escalates, Dai discovers his true heritage as the son of Baran, one of Vearn’s powerful Dragon Riders. Baran brainwashes Dai to erase his human memories, aiming to purge humanity for its cruelty. Through Popp’s monumental, self-sacrificing stand—which temporarily costs the wizard his life—Dai’s memories are restored, and
father and son reconcile just as Baran turns against Vearn to
save the world.The ultimate conflict pits Dai and his battle-hardened allies against Vearn’s elite guard, culminating in a harrowing war to prevent Vearn from dropping the Black Core-laden Vearn Palace onto the surface world to obliterate humanity. Popp returns, hailed as a true hero of humanity, while Hyunckel and Crocodine push their bodies to the absolute brink.In the climax, Dai unlocks the full, devastating potential of his dragon crest and masters the Avan Strash. He confronts Vearn in a breathtaking final duel that shatters the heavens and earth. Dai defeats the Dark King, but the victory demands a heavy price. To neutralize Vearn’s final, catastrophic trap, Dai carries the volatile remnants into the upper atmosphere, seemingly sacrificing himself in the explosion. Though his physical body vanishes, leaving behind only his sword, his indomitable spirit and legacy of courage live on through Popp, Maam, and his surviving comrades, who continue to protect the peaceful world Dai fought so desperately to save.