All Nikolai ever wanted was to be happy. At a very young age he was told he was special, and grew up believing it. He has the power of seduction, and has used it on several women to get what he wanted. He even used it on his brother's wife, Regan, and eventually stole her away.
Nikolai then took her to America where he learns that life outside of his coven is very different. In order for him and his new woman to survive in this new country, they needed the safety of a clan, and they find one.
However, the one they join happens to be deeply rooted in organized crime. Nikolai and Regan planned to stay forever until their master makes a move on Regan. Nikolai refuses to have his woman stolen away, so they move on. Because of the way they were treated, Nikolai vows to one day go back. Fifteen years later he does. His plan is to kill his former master, and live happily ever after.
Some how, that doesn't happen.