Boku wa Isekai de Fuyo Mahou to Shoukan Mahou wo Tenbin ni Kakeru

One day, in a private school with dormitories, the whole school was transported in a whole other world. Gaya Kazuhisa has been bullied for a long time already. She hopes to kill the one who had bullied her, so she made a trap, only for her to kill a monster instead. From that moment, she realized her ability to go against monsters.