为和圣女老婆结婚，只好打倒魔王 (Associated Names)

[Single heroine + black belly + kendo genius + daily life (probably) + love + adventure + light novel] Leo, the inheritor of the ancient swordsmanship school, went down the mountain to join the world in order to save the declining kendo gym, and entered the whole continent as a commoner In the famous aristocratic…

Leo, the heir of an ancient swordsmanship school, descends from his seclusion to save his declining dojo. Disguising himself as a commoner, he enrolls in a renowned aristocratic academy known across the continent. Intending to stay low-key, he unexpectedly encounters his destined partner. In his quest to marry her, Leo finds himself compelled to defeat…