Kaiki Shita Ken Sei no Mahou Riron

All who stand against monsters are eventually forced to make a choice. One path is that of the mage, wielding magic capable of creating supernatural miracles. The other is the path of the swordsman, mastering inhuman techniques through sheer skill. Oscar, a swordsman, had swung a blade since early childhood and rose to the rank of the highest Sword Saint. He cut down ferocious monsters, earned the admiration of the people, and lived a life envied by all. Yet deep within his heart, he harbored a secret longing— an unfulfilled admiration for the path of the mage…? Original Webtoon