Yuu☆Yuu☆Hakusho (Yu Yu Hakusho)
Urameshi Yuusuke, 14 years of age, is about as troublesome and violent as teenagers come. He is constantly ditching school, causing uproar, and getting into numerous fights everyday. One day however, he does the unexpected: sacrificing himself to save a young child. Such an action was never ever expected, especially coming from someone as troublesome as Yuusuke. The afterlife is not prepared for Yuusuke, as they never thought he would make such a sacrifice. Nowhere to go, and dead, Yuusuke becomes a ghost and must earn his way back into existence.
Yuusuke is "employed" by Koenma, who is in charge while his father and ruler of the afterlife, King Enma, is away. Under Koenma's command, Yuusuke helps to stop menacing demons that threaten the lives of people everywhere - whether by stealing priceless and invaluable items and destructive weapons, or by wreaking havoc on humans.
Throughout Yuusuke's journey, he is usually joined by his arch-rival, and local bully, Kuwabara Kazuma; he is also joined by two demons named Hiei and Kurama, who are ex-convicts of the afterlife that managed to escape from Koenma.
This group of unlikely allies goes on to participate and struggle in battles that have outcomes that determine the fate of humanity!