Valentin Cassadine is a fictional character from General Hospital, an American soap opera on the ABC network. The character was initially conceived in 2009 by head writer Robert Guza Jr., as a previously unknown member of the wealthy Cassadine family looking to wreak havoc on both the Cassadine and Spencer families. But initial plans for the character's introduction were delayed and completely abandoned by 2010. In 2016, it was announced that All My Children alumnus James Patrick Stuart had joined the cast in the mystery role of Theo – who is revealed to be Valentin. Valentin is known for being the most evil of the Cassadine sons, having been disowned by his father at a very young age. At one point, he poisons his mother Helena (Constance Towers). Stuart's performance has been met with critical acclaim, having garnered him a Daytime Emmy Award nominations for Outstanding Supporting Actor in a Drama Series in 2020 and 2021.