The Mad Mob Characters Unknowingly Destroys the Main Story

Albert, the youngest son of the border noble Falconer family, has a secret: he is a reincarnated person from another world. The Falconer family is one of the most skilled fighting families in the border, and he was raised on the battlefield from an early age. One day, at the age of 14, he realizes that this world is exactly like a game he played only once in his previous life. However, his memories of that game are vague. In the end, he was a "mob character" whose name doesn't even appear. As Albert begins to question the meaning of his existence, he decides to enroll at Radford Royal Magic Academy, the setting of the game...!? (Source: Futabasha, translated)