My Brother Reincarnated as a Saint, and I Transformed into a Magical Girl?

After the brother who finished the college entrance examination failed to confess his love to Qingmei, he was killed by a monster from another world and was saved by an unknown angel. He thought he was reincarnated into another world to be Long Aotian who didn't eat beef. What does it mean that my brother wants to be reincarnated into another world and become a saint there to save the people? What does it mean that I have to stay here on Earth and be a magical girl to save the world? Fuck Mozi! We are men!