"Monster" is a psychological thriller anime adapted from Naoki Urasawa's manga, airing from 2004 to 2005. It follows Dr. Kenzo Tenma, a neurosurgeon in Germany who saves a young boy, Johan Liebert, despite being told to prioritize a politician. Johan grows up to become a malevolent force, leading Tenma to be wrongly accused of being a serial killer. As Tenma hunts Johan to stop his reign of terror, he confronts deep questions about morality, identity, and evil. The series is known for its complex characters, philosophical depth, and exploration of trauma and redemption, making it a standout in the psychological thriller genre.