Monster is a critically acclaimed seinen manga written and illustrated by Naoki Urasawa. The story follows Dr. Kenzo Tenma, a brilliant surgeon who saves the life of a young boy named Johan. However, Tenma soon discovers that Johan is a dangerous sociopath who goes on a killing spree. As Tenma tries to stop Johan, he becomes entangled in a web of conspiracy and must confront his own moral dilemmas. With its complex characters and gripping storyline, Monster is considered one of the best seinen manga of all time.