Jishou F-Rank no Oniisama ga Game de Hyouka sareru Gakuen no Chouten ni Kunrin suru Sou desu yo?  

Dear Self-styled F rank bro' says, he's gonna rule a game-oriented school., 自称Fランクのお兄さまがゲームで評価される学園の頂点に君臨するそうですよ?, 自称Fランクのお兄さまがゲームで評価される学園の頂点に君臨するそうですよ？

Shishio Academy is a renowned institution in Japan that primarily accepts students who excel academically, athletically, or come from distinguished backgrounds. In reality, however, it fosters a competitive environment where success is determined by performance in games. This results in a ruthless competition where only one winner can emerge victorious. Guren, known as a legendary figure in the shadow world, possesses invincible abilities but desires a normal life free from conflict. Despite failing the entrance exams on purpose and being assigned the lowest grade F, his situation changes when his sister Karen faces danger. At this point, Guren reveals his true capabilities.