Saijaku Muhai no Bahamut

Five years after a violent rebellion toppled the Arcadia Empire, its former prince, Lux, finds his life upended by a single careless mistake. After accidentally wandering into the bathing quarters of a female dormitory, he catches sight of Lisesharte, the princess of the newly established kingdom. Furious at the intrusion, she immediately challenges him to a duel using Drag-Rides—massive, ancient mechanical suits of armor excavated from ruins scattered across the globe. Once celebrated as the most formidable Drag-Knight in existence, Lux now carries the paradoxical title of the "undefeated weakest." Despite never having lost a match, he adheres to a strict personal code: he absolutely refuses to strike an opponent in battle. This unusual philosophy defines every fight he enters, including his tense confrontation with the vengeful princess. The aftermath of their duel sets Lux's fate on an unexpected course. Rather than facing punishment for his trespass, he is drawn into the very heart of the new regime's power structure, ultimately enrolling in an elite, all-female academy dedicated to training royalty as Drag-Knights. Thrust into a world governed by those who overthrew his family, the former prince must navigate a complex web of politics, pride, and combat while remaining true to his unyielding vow never to attack.