Complex sentence: She was put into an orphanage when she was ten years old when a rouge vampire attacked the orphanage, Saboten escaped and wandered into Cross Academy, where Headmaster Kaien Cross had looked after her until she was fourteen.
Split into simpler sentences: She was put into an orphanage, she was ten years old when a rouge vampire attacked the orphanage, Saboten escaped and wandered into Cross Academy. Where Headmaster Kaien Cross had looked after her until she was fourteen.