The main character hides his strength

"Face your destiny." In the alternate realm of the Otherworld—filled with creatures and Earth's catastrophes—an ancient warrior, a human summoned long ago into the realm, is determined to bring it all to an end. Fueled by the resentment of an unknown past, this journey unravels hidden identities, embarks on undercover missions, faces death trials, navigates through betrayals, and wades through bloodbaths. What do the shadows conceal, and what destiny awaits in the heart of the unknown?