Post-Apocalyptic Orphanage Story

In the post-apocalyptic era, the heroine, whose father died, entered the "Orphanage", a refuge for girls. After awakening the skills, he fell in love with other girls and killed each other. It turns out that there is another reason for my mother's death, and several major bases in this world are competing with each other. Is the dean the real murderer? What stories are about to happen at the end of the world? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.