Mark Blackthorn is a fictional character from the Shadowhunter Chronicles, a series of young adult novels written by Cassandra Clare. He is a member of the Blackthorn family, known for their strong ties to the Shadow World, which includes demons, angels, and other supernatural beings. Mark is half-fae, giving him unique abilities and a distinct appearance. In the series, Mark is portrayed as brave and loyal, often facing challenges to protect his family and friends. His character explores themes of identity and belonging, particularly as he navigates his mixed heritage and the complexities of the Shadowhunter society.