Monster is a Japanese manga series written and illustrated by Naoki Urasawa. It was published by Shogakukan in their Big Comic Original magazine between 1994 and 2001, with the chapters collected and reprinted into 18 tankōbon volumes. The story revolves around Kenzō Tenma, a Japanese surgeon living in Germany whose life enters turmoil after getting himself involved with Johan Liebert, one of his former patients who is revealed to be a dangerous psychopath.
Dr. Kenzō Tenma is a young Japanese brain surgeon, working at Eisler Memorial Hospital in Düsseldorf. Tenma is dissatisfied with the political bias of the hospital in treating patients, and seizes the chance to change things after a massacre brings fraternal twins Johan and Anna Liebert into the hospital. Johan has a gunshot wound to his head, and Anna mutters about killing; Tenma operates on Johan instead of the mayor, who arrived later. Johan is saved, but Mayor Roedecker dies; Tenma loses his social standing. Director Heinemann and the other doctors in Tenma’s way are mysteriously murdered, and both children disappear from the hospital. The police suspect Tenma, but they have no evidence and can only question him.