No Way! The Cannon Fodder Female Supporting Character Is Actually a Genius Big Shot - Chapter 36

The world that nurtured the civilization which reached the pinnacle of magic was on the verge of destruction.
The last survivor transmigrated to the past, when the magic civilization started growing, as countless mages were still fumbling their ways through the thorny paths of magic knowledge.
He, who came from the end of the magic era, aim to reach the pinnacle of magic.

- Description from Novelupdates

Rainer, an amateur arcanist and college student, sought to create a new spell far surpassing the magic of the few he inherited from his grandfather. Yet the interference of an unknown event during the casting of his spell led him to be thrown through space and time.

Lachlan, once a victim of deceit and betrayal, wakes up to find himself back in his high school days, just before his life took a dark turn.With a newfound system that grants him immense knowledge and skills, Lachlan vows to change his fate and protect his love, Julius. As he navigates through old rivalries and new opportunities, will Lachlan succeed in rewriting his destiny and exposing those who wronged him?