- Full Name: Prince Nikolas Mikhail Stavrosovich Cassadine
- Actor: Tyler Christopher (1996 - 1999, 2003 - Present)
- Actor: Coltin Scott/Stephen Martines (1999 - 2003)
- Parents: Stavros Cassadine and Laura Spencer
- Siblings: Lucky and Lulu (Lesley Lu Spencer) ~ Half-brother and sister
- Relationships:
- Katherine Bell ~ Nikolas' first lover, older woman who ended up becoming engaged to Nikolas' uncle Stefan
- Sarah Webber ~ Teenage romance that went sour after Nikolas was shot in the neck.
- Gia Campbell ~ Nikolas' first big love, was engaged up until early 2003
- Emily Bowen-Quartermaine ~ Long-time friends, Nikolas and Emily fell in love while Emily was sick from breast cancer
- Courtney Matthews ~ Nikolas began an relationship with Courtney while married to Emily. Courtney has since passed away but not before giving birth to Spencer; her son with Nikolas
- Is the heir to a great Russian Throne, raised by his uncle Stefan, well educated and spoken
- Nikolas' paternity has played a large role in his upbringing; was his father Stavros or Stefan... Stavros!
- Came to Port Charles as an adult in 1996
- Saved Lulu's life as a young child by donating bone marrow
- While involved with Katherine, she planned to trap Nikolas into marriage by having a baby/miscarriage but ended up dying a violent death by falling from the parapet.
- Was shot in the throat and became close friends with Emily
- Nikolas' relationship with Gia Campbell was intense and culminated after the Face of Deception campaign, however it did not last.
- Nikolas has many issues with his grandmother Helena, his mother's husband Luke Spencer and his mentally ill mother, Laura
- Was in prison for murdering Helena but charges were dropped when she showed up alive
To read Nikolas' full biography, please click HERE!