- Siblings: Irina Derevko (deceased), Katya Derevko
- Nieces: Sydney Bristow, Nadia Santos (deceased)
- Grandnieces & nephews: Isabelle Vaughn, Jack Vaughn
Before Season 4
Elena was one of the KGB's foremost assassins, responsible for the murder of countless diplomats and politicians throughout Eastern Europe. Thirty years before Season 4, Elena disappeared and could not be found even by her sister Irina. Little did they realise that Elena had posed as "Sophia Vargas", the head of the orphanage Nadia Santos, her niece, was at (A Clean Conscience).
A hit was ordered on Sydney Bristow's life and Jack Bristow believed it was ordered by Irina (Resurrection). In retaliation, Jack found Irina and shot her (Another Mister Sloane). He did not realise that firstly it had been Elena who had ordered the hit under the guise of Irina, and secondly that he had in fact shot a doppelgänger of Irina's (Search And Rescue).
Around a year before Season 4, Arvin Sloane and Jack Bristow had been investigating the whereabouts of Elena. Jack received a message from an old associate that led him to one of Elena's safehouses in Warsaw. Inside was detailed information on the lives of Sydney Bristow and Nadia Santos, her nieces, with evidence suggesting she had them under surveillance for at least a decade. They assumed she was responsible for the attack on "Sophia", not realising that she in fact was Sophia (A Clean Conscience).
Elena arrived in Los Angeles, disguised as "Sophie Vargas". She used her former connection to Nadia to stay with her and Sydney so as to monitor their work for the CIA. She claimed to have been attacked in her home in Lisbon, Portugal, the reason for her coming to the United States. She gave Nadia a necklace with St. Marcos on it, who Nadia's orphanage was named after. Nadia took it, but did not know that Elena had implanted a microphone into the necklace so she could monitor Nadia's conversations and CIA work (A Clean Conscience).
She later offered to cook dinner for Sydney, Vaughn, Nadia and Weiss. Sydney and Vaughn were unable to make it because of Jack's illness, so only Nadia and Weiss attended. Elena took the opportunity to have her associate, Avian, hack into Nadia's laptop and request to move the Hydrosek, a deadly weapon, to an unsecured location away from APO. Elena and Avian then went to the site and stole the weapon before Nadia and Weiss could arrive to stop them - albeit not realising who it was that stole it (Mirage).
Elena sent a team into the Department of Special Research to steal all the Rambaldi artefacts necessary to complete "Rambaldi's endgame". On the same night, she left Sydney and Nadia's house, saying that she had been informed by the Lisbon police that it was safe for her to return. Hours later, Hayden Chase entered the house and accused Nadia of working against the government and allowing the team to break into the DSR. It was at this point that Jack and Sloane began to realise that Sophia was Elena, which was backed by the microphone found in the necklace given to Nadia by Sophia (The Descent).
Sloane deduced that Elena would go to Lazlo Drake with the Rambaldi artefacts. Sydney and Sloane went to meet him, but he was already dead. Sydney found a hidden camera and rewound the feed to see Elena talking with Drake. Before she can see where they planned to take the Rambaldi artefacts, Sloane tranquillized her and left. He met up with Elena in her office in Prague and offered his services to help complete what she was doing. Dixon, Nadia and Sydney were sent on a mission to try to stop them. Dixon found Elena and Sloane, but Elena shot him before he could react. When in the hospital, Dixon told Sydney that he saw Irina Derevko before being shot by Elena, who had Sydney's mother in captivity (The Descent).