Valentin Cassadine (as played by James Patrick Stuart on General Hospital)
* Son of Mikkos Cassasdine.
* Helena Cassadine is his step-mother.
* Disowned by Mikkos.
* First appeared on Cassadine Island in 2016 after years of lead-up.
* Claimed to be a fisherman named Theo to Sam and Jason Morgan but had a tattoo of the Cassadine family crest on his arm. His real identity was revealed days later.
* Shot Nikolas when he tried to save Ava Jerome.
* Shot Dr. Kevin Collins as he tried to save Laura Spencer.
* Had sex with Nina Reeves.
* Tried to kidnap Spencer Cassadine.
James Patrick Stuart (July 11, 2016 - present)
First heard of in 2009, Valentin Cassadine had been disowned by his father Mikkos Cassadine and at one point poisoned his step-mother, Helena. Valentin did not appear until 2016 under the alias of Theo, a fisherman forced to land on Cassadine Island because of bad weather. Jason and Sam Morgan agreed to let him stay on the island, but a few days later he held them, Ava Jerome and Nikolas Cassadine up at gunpoint, demanding the Cassadine fortune in exchange. Nikolas was shot trying to save Ava, and Kevin Collins was also shot trying to save Laura Spencer.
Valentin escaped in the tunnels and turned up soon after in Port Charles. He met Nina Reeves and they had sex, but the next morning he left to attempt to kidnap Spencer Cassadine. He was stopped by Sonny Corinthos and arrested by Curtis Ashford. As he was about to be extradited to Greece he promised Nina they would meet again.
Mikkos Cassadine (father -deceased)
Alexis Davis (half-sister)
Stavros Cassadine (half-brother - deceased)
Stefan Cassadine (half-brother - deceased)
Anthony Cassadine (uncle - deceased)
Victor Cassadine (uncle - deceased)
Nikolas Cassadine (nephew)
Spencer Cassadine (great-nephew)
Petros Cassadine (first cousin)
Charlotte (using Lesley Lu "Lulu" Spencer Falconeri's embryo via surrogate with Claudette Beaulieu)