BIOGRAPHY OF BLEACH
Ichigo Kurosaki is a normal high school student, or he thinks so. One night he sees a shinigami (death god) named Rukia Kuchiki. She is surprised that normal humans can’t see shinigami. Their conversation is interrupted by a holllow (evil monster), Rukia is injured and she transferred some of her power to Ichigo to fight against the evil one.
Inadvertently, Ichigo absorbs almost all her powers and defeats the hollow. The next day Rukia comes to Ichigo's class dressed like a normal human; she says she can’t return to his world because she has lost almost all their energy and will leave when recovered. Since then, Ichigo and Rukia fight together against the hollows through different situations.