Johan Liebert is the titular "monster" and main antagonist of the Monster series. He is the older twin brother of Nina Fortner, formerly known as Anna Liebert. Johan was shot in the head in 1986, but he was operated on and saved from death by Kenzō Tenma.
Johan has spent portions of his life in different locations under different aliases, and possesses extraordinary levels of charisma and intelligence. He tends to use his gifts to cruelly manipulate and corrupt others. 