Reconstructing the Threshold of Destiny

Reincarnated as the protagonist of "Adventure Legend"? He originally thought so, but after hearing his name from his mother's mouth, he suspected that he had heard it wrong. That was the name of a classmate who betrayed the protagonists in the middle of the story. He was also the mysterious strong man who pushed the world into the abyss of despair and hid in the darkness to wreak havoc. Lian, who hopes to live a peaceful life, decides to quietly stay at the border.