From the Start, I Signed In and Somehow Became the Thunder Emperor

Gu Fan, a pure-hearted but clueless college student from Blue Star, dives in to save a young woman in trouble and suddenly finds himself in the Tianxuan Continent. He is picked up by Zhang Qingtian, the passing master of Qingyun Peak at the Luoxia Sacred Land, and taken in as a disciple. But with his terrible aptitude, all he can do is give up trying. Twenty years later, a sudden System disrupts his peaceful life. “Ding! Congratulations, Host. You have obtained a sign-in System. Would you like to bind it?” Gu Fan pauses. For twenty years, he never got depressed, even though he couldn't cultivate. He smiles and shakes his head, then focuses on the fishing rod in his hands...

The synopsis is short. Please read the main story for more.