King: Kidnap Doria at the beginning

Chu Feng accidentally traveled to the King's Continent and became a prisoner who was asked to fight against the demons. At the critical moment, the protagonist awakened the system and obtained an immortal demon body. With despair as a sword and the dead as armor, Chu Feng, who gained the power of the demons, continued to grow stronger and let his opponents know what it means to be truly invincible. (This book is a King's fan fiction, not a cool one, with a lot of original content. It doesn't matter if you haven't played the game, you will definitely understand it!)...