Jeremiah Valeska is a fictional character from the television series Gotham, which aired from 2014 to 2019. He is portrayed by actor Cameron Monaghan and is known for being a key antagonist in the series. Jeremiah is depicted as a highly intelligent and manipulative individual, often using his cunning to achieve his goals. In the show, Jeremiah is the twin brother of Jerome Valeska, another character who embodies the traits of the Joker from the Batman comics. Jeremiah's character evolves throughout the series, ultimately becoming a version of the Joker himself, showcasing his descent into madness and his obsession with chaos.