Ronald Peller is a National Security Agency official. He's a deep cover operative who worked unwillingly for The Shop.
He married a girl named Rosemary. He had three children with her. A son, Lyle, daughter, Lily and the youngest son, Lionel. Lionel was an accident and he never cared too much about him. Lionel showed interest in computers. After Lionel failed at school because he had a pet spider, Ronald decided to kill the spider and send Lionel to military school. Lionel refused, faked his death and changed his name to Seymour Birkhoff.
At the end of "Dead or Alive" Birkhoff searches for the The Shop's agent in NSA. He sees a photo of Ronald Peller. Ryan asked Birkhoff if he has found anything about The Shop's agent. Birkhoff deleted the info he has just found and told Ryan that he still has no luck in finding him.
In "Set-Up" it was revealed that he is Birkoff's father. The real one is in M.D.K. Office in Dubai while the other acts a a double. Birkhoff sends him encrypted messages to let him know that he is alive. As the other got captured he was forced to inform the other through his glasses in an attempt to convince Nikita he was the real Ronald Peller. As Amanda realized she got played she ordered the fake to attack Birkhoff, after which he got killed.
Amanda talked to him and said that he was the building blokes of which Birkoff got created. She told him she was not allowed to perform extreme measures on his son in the past but she was her own boss now.
In "Pay-Off" his son saved him from captivity.