幽游白书

A fourteen-year-old delinquent, Yusuke Urameshi, dies after being hit by a car while saving a child. Since the Spirit World did not anticipate his death and had no place for him, he is given a chance at rebirth. After passing the trials of the Spirit World, Yusuke finally returns to his own body and becomes a Spirit World Detective. During one mission, Yusuke meets Kurama and Hiei. Together with Kuwabara (Yusuke's best friend), the three of them solve numerous cases for the Spirit World. Later, at the "Dark Tournament," they defeat powerful opponents, and their strength and friendship grow day by day. To stop former Spirit World Detective—Shinobu Sensui—from opening a passage between the Demon World and the Human World, Yusuke and the others enter the Demon World. Yusuke is even "killed" by Sensui, but it turns out Yusuke is actually a descendant of demons, allowing him to revive. With the help of his father, Yusuke finally defeats Sensui, and everyone returns to the Human World. The battle between Yusuke's group and Sensui attracts the attention of demons in the Demon World. The three most powerful factions—Yomi, Raizen, and Mukuro—each extend invitations to Yusuke, Hiei, and Kurama, hoping they will become their assistants. Yusuke, dissatisfied with Raizen for "helping" him during his fight with Sensui, decides to go settle the score. Hiei, seeking more combat opportunities and experience, accepts Mukuro's invitation. Kurama, due to past grudges, has no choice but to accept Yomi's request. All three return to the Demon World and, within less than a year, become the second-strongest in their respective territories. A year later, Raizen dies, and Yusuke becomes the ruler of his territory. He proposes a Demon World Unification Tournament, where the winner becomes the ruler of the Demon World, while the losers must obey the winner's commands. The winner of the first Demon World Unification Tournament is Raizen's old friend—Enki. He establishes the rule of "no interference with the Human World" and proposes holding the same tournament every three years. After the tournament, Yusuke and Kurama return to the Human World, while Hiei decides to remain in the Demon World.