What Can I Do to Save My Brother Xiayou?

Fujimaru Ritsuka returns home from Chaldea. When he opened the door, he saw that his brother, whom he had not seen for many years, was driving the monster to kill his relatives. Fujimaru Ritsuka instantly felt the malice of the world. Ask, how to save the rebellious younger brother who did not graduate from the second semester of high school and wants to destroy the world? You go this way. We all make mistakes. My sister is back, and your dream of becoming a middle school student can be declared shattered. Save humanity, the master with countless heroic spirits said this. 1. The timeline is confusing. 2. Just have fun and don't delve into it. 3. Very short. 4. Cp undecided Intention: Looking at the world, you and I are all mortal.