Magus Tale: Sekaiju to Koisuru Mahoutsukai  

MagusTale ～世界樹と恋する魔法使い～

Is it possible that you are dreaming? You arrived at the island to inform your younger sister, Koyuki, who attends a boarding high school located there, about our father's disappearance. However, you were mistaken for an intruder and attacked with magic. Your injuries are severe, but thanks to Koyuki, you would have lost your life without her help. The reason behind the school's isolation is that it serves as a training ground for magicians. As a result, your new life on the island has begun.