
Nikolas Cassadine, born Prince Nikolas Mikhail Stavrosovich Cassadine first appeared in Port Charles as an adult in 1996. Born to Stavros Cassadine and Laura Spencer at the Cassadine estate in Greece, Nikolas is heir to a great Russian throne and has gone through a lot in his years. A hatred for the woman who was his mother had been instilled in him since birth by his grandmother, Helena after Laura's husband Luke had rescued her from the island and Stavros had been killed. Raised by his uncle Stefan, Nikolas had the very best of education.
In coming to Port Charles, Nikolas tried to keep his distance from Laura but felt inevitably drawn. After saving his little sister's life, LuLu (daughter of Luke and Laura) by donating bone marrow, the Spencer/Cassadine feud that had lain dormant for many years erupted as Luke found out about Laura's eldest son. Luke had not known about Nikolas' exsistence before this time and forced Laura to choose between their family and her son. Torn, she chose their family and essentially abandoned Nikolas again only to have Stefan force her hand by threatening the solvency of General Hospital if she put up a fight against Stefan and Nikolas staying in Port Charles.
During his first months in Port Charles, Nikolas became close to Nurse Bobbie Spencer who eventually married Stefan. The marriage quickly turned sour after Nikolas learned that Bobbie had betrayed Stefan and the friendship was lost. Nikolas' next friendship quickly turned into a love affair with Katherine Bell, an older woman after Laura had faked her death to escape the Cassadine threats. Nikolas and Katherine continued to spend time together until Katherine was found shot at Wyndemere by Stefan who had thought she was an intruder.
Nikolas eventually discovered that Laura had faked her own death and he banished her from his life; remaining close to his sister, LuLu. Deciding to attend public school, Lucky Spencer, Nikolas' half-brother became jealous when Nikolas started to date Sarah Webber, the girl that Lucky had a crush on. Nikolas' life took a drastic turn off-road when he was shot in the neck at Luke's one night, a victim of mob-violence and a bullet meant for mob enforcer, Jason Morgan. Jason performed an emergency tracheotomy and saved Nikolas' life but Nikolas was left with a condition known as Broca's Aphasia which left him unable to speak for a long period of time. Ashamed of what had happened to him, Nikolas became severely depressed and shut Sarah out by refusing to see her. Nikolas, did however, respond to Robin Scorpio and she helped him through the worst of his times and speech therapy. Although, grateful for the help that Robin had given his nephew, Stefan disapproved of their friendship due to the fact that Stefan had had problems with Robin in the past and that she was also involved with Jason Morgan. Despite Stefan's protests, the duo remained good friends.
Meanwhile, Katherine and Stefan had become close and eventually engaged. On the evening of their engagement ball at Wyndemere, Katherine plunged to her "death" after realizing that Stefan was still in love with Laura Spencer and that he was Nikolas' father. Nikolas was devastated however, Katherine returned from the dead later on in the year after being kept alive by Helena. Katherine revealed the news that she had learned to Nikolas about his parentage and after initial anger, Nikolas was happy. He was now free to have a family but also relieved as his duties as prince.
Now, the man was able to focus on the friendship that he had formed with Emily Quartermaine, Liz Webber and Lucky Spencer, aka "The Four Musketeers". The quad teamed up to expose the person who was blackmailing Emily. Nikolas learned to finally trust his brother and the two formed a tight relationship. After the blackmailing mess had been solved, Nikolas began a serious relationship with Katherine. In an attempt to solidify herself within the Cassadines, Katherine faked a pregnancy causing Nikolas to propose to her. Futilely, Katherine tried numerous times to conceive using in-vitro fertilization but she was unable. On a stroke of luck, Katherine schemed a plan to have a "miscarriage" at her wedding that would be indirectly caused by Laura. Then, she'd find out that she couldn't have kids again and Nikolas would be honor-bound to stay with Katherine and blame Laura. Katherine confessed her plan to an unconscious Helena who actually heard the plan. On the night of the wedding, Helena pushed Katherine off the same parapet as before and Katherine fell to her actual death. Nikolas suspected Laura of pushing Katherine off but then learned of Katherine's deception in the final end.
The next tragedy in Nikolas' life occurred when Lucky was presumed dead after a fire claimed his apartment building. As the grieving process commenced, Nikolas became close to Lucky's girlfriend, Liz. Nikolas eventually grew to have feelings for Liz but knew that they would never be reciprocated in kind. A year after Lucky's death, Nikolas learned that there was a possibility that Lucky was still alive. Liz and Nikolas found Lucky in New York City but he was not the same man that he once was. Lucky urged Nikolas to have Liz but they were having none of it and it was discovered that Lucky had been brainwashed by Helena to forget his love for Elizabeth. After intensive therapy, Lucky's feelings of love returned and Nikolas once again dealt with the question of his paternity.
Finally, it was revealed that Stavros was in fact, Nikolas' biological father and Nikolas was heir to the throne. Helena had once again deceived them all in order to gain access to the Cassadine money and loved to toy with Stefan’s emotions. Months later, Stefan "died" at Luke Spencer's hands but in actuality, Stefan had faked his death to avoid Helena. Nikolas was unaware of this and mourned his uncle's passing.
Nikolas, then met his next love, Gia Campbell. Gia was a friend to Nikolas when Stefan came back from the dead and eventually their mutual attraction was given into after the Face of Deception campaign debacle. As their romance blossomed; Helena's dastardly deeds were blown up and put on full display after she had cryogenically unfrozen Nikolas' dead father, Stavros along with continuing to control Lucky's mind. Nikolas and Stavros came face to face in the end. Ultimately, after kidnapping Gia and Laura, Stavros met his maker at the hands of one, Luke Spencer. Nikolas and Gia's relationship grew and then grew apart. They were at one time engaged but after mishaps and miscommunication, they grew apart and eventually broke up. Nikolas meanwhile, helped Lucky out of some jams and tried to protect them from the wildness of Luke after Laura had her mental breakdown.
The story now leads into the love story of Nikolas and Emily....