Madou Kensei -Densetsu no Kikan-

The legendary hero, known as the "Mage" for his unparalleled magic and the "Sword Saint" for his unmatched swordsmanship, returns to a world 1000 years after his time. Balua Westgarden, the "Magic Sword Saint," once mastered both magical and martial prowess, inscribing his name at the pinnacle of human history. He faced the absolute demon king Giranher in a battle that would determine humanity's fate. However, due to the interference of mysterious forces, both Balua and Giranher perished. For a millennium, Balua's soul lingered in the world, bound by regret for not completing his mission. When Direa Westgarden, a boy who idolized the Magic Sword Saint, was mortally wounded by monsters, Balua seized the opportunity to return to the mortal realm by inhabiting Direa's body. Original Webtoon.