Shikkakumon no Saikyou Kenja: Sekai Saikyou no Kenja ga Sarani Tsuyokunaru Tame ni Tensei Shimashita  

失格紋の最強賢者～世界最強の賢者が更に強くなるために転生しました～

In this realm, there lived an individual renowned for their mastery of magical combat. They were referred to as "Sage." Driven by the pursuit of the most potent martial arts, they dedicated themselves to studying every available magical and combative discipline. Despite their conclusion that their physical form was unsuitable for magical combat, they persevered. They imbued their spirit with a powerful enchantment, and were subsequently reborn into a distant epoch. Upon arriving in this new world, they discovered that its magical theory had regressed to an astonishingly low level.