Cheat Majutsu de Unmei wo Nejifuseru

Cheat Majutsu de Unmei wo Nejifuseru summary:

Summoned from a different world, Souji was the strongest magician. This is because all the magic theory that he developed in-game became “real”. Furthermore Souji knew the “events” that were going to happen from now on. This world is moving according to the history in the game.
Souji rescues many beautiful heroines from their miserable fate one after another. As their beauty and abilities aren’t inferior, they became Souji’s “comrades”. The strongest magic theory, and the strongest bishoujo party. Souji, who has all the elements to become the strongest, marches forward! This is the tale of him rising to the strongest transcendence!