Tenkomori: The Homecoming Club Conquers Another World - Chapter 98.5 - The Second Year at the Academy - Consequences of a Chain (5)

Kiyoshiro Takeda lived a life without purpose, drifting through his days with no direction. But one fateful moment changes everything. Now, he finds himself in a world unlike any he has ever known, given a role he never asked for. A new life, an unknown destiny, and a looming catastrophe that only he can prevent. But can someone who failed in his old life truly become the last hope?

Xin Yun, a sarcastic young man, traveled to an unknown world by chance, but lost his chance to become the strongest because of his obsession with women... or sex. In a collision of the powers of nine powerful men, an incredible thing happened. Xin Yun was reborn back to the time when he traveled to the Isekai world. A fantasy journey is about to begin... [The comic adapted from this novel is popular all over the world]

Childhood sweethearts.
The most popular person in school is my childhood sweetheart.

- Description from Novelupdates

Lin Chen was persecuted by his childhood sweetheart and accidentally obtained an ancient legacy. From then on, he embarked on a path against the heavens!“I am a sovereign! Those who insult me will be killed, those who obstruct me will die!”