Saijaku Muhai no Bahamut  

Undefeated Bahamut Chronicle, 最弱無敗の神装機竜《バハムート》, Saijaku Muhai no Shinsou Kiryuu, บาฮามุท มังกรเหล็กไร้พ่าย, 最弱無敗の神装機竜

Once upon a time, Lux, who was once a prince of an empire that fell five years ago due to rebellion, met Lizsharte, the princess of the new kingdom, by chance while breaking into the girls' dormitory bathroom. "What are you doing here?" asked Lizsharte, to which Lux replied, "I don't know, I must have gotten lost." Lux was known as the strongest Drag-Knight in history until he was defeated by Lizsharte in a duel that started with her challenge. As a result of his defeat, Lux became known as the "Weakest Undefeated," a Drag-Knight who refused to attack. Now, Lux is about to embark on an adventure at the girls' academy where he will be surrounded by noble young women from the academy. This marks the beginning of the ultimate fantasy battle between the right and might.