Death Note (2006 Anime Series)

High school genius Light Yagami discovers a Death Note, a notebook dropped by a bored Shinigami (Death God), that allows him to kill any person whose name he writes in it. Adopting the alias Kira, Light begins a global crusade to eliminate criminals and create a new, peaceful world. His god complex brings him into a deadly, high-stakes battle of wits against L, the world's most brilliant detective, who is determined to expose Kira's identity.