Lucian Nisard was a follower of Elena Derevko.
Before Season 4
Nisard was on the ten most wanted list for crimes involving falsifying documents, espionage, conspiracy to commit murder and manslaughter (Search And Rescue).
Later, he was in a bar in Ibiza. APO tracked his flight records and found him there, and sent Sydney and Vaughn to extract information from him. They found records referring to "Helix" on his phone, and forced him to admit that Irina Derevko was alive, under the protection of her sister Elena. He began to laugh manically, saying that a follower agreed to become Irina's doppelgänger. He said that she was being kept in a remote location in Guatemala called Tikal.