World War II
Sasha Demidov was a Soviet Armed Forces soldier in the 478th Regiment. In cooperation with John McGinnis of the United States Army, Demidov's regiment went to Finow to stop the Nazi advancement. McGinnis used the Midnight Oil on the Soviet soldiers to defeat the Nazis, however, the 478th regiment killed each other, although Demidov survived. The gas damaged Demidov's larynx to the point that it had to be removed.
Sasha Demidov was recruited by the Leviathan along with Leet Brannis. Demidov was deprived of his larynx, and even of his name, becoming a silent assassin for the organization. Demidov went to La Martinique where he stood by the bar and watched Peggy Carter go into Spider Raymond's office. Once she had left, he walked into the office and discovered Raymond rummaging through his safe, trying to find the Nitramene bomb that Carter had just stolen. Raymond pleaded with Demidov that he could fix the situation and reacquire the bomb, but Demidov did not listen and shot him in the head instead. As he ran outside to try and find the Nitramene, he noticed Carter getting into a cab.
At the residence that Carter shared, Demidov found Colleen O'Brien resting in and killed her with a single shot to the head as he searched for the bomb. Meanwhile, Carter was in the bathroom deactivating it. She emerged from the bathroom to find her roommate dead and Demidov aiming his gun behind her. Carter appeared for formidable than Demidov had anticipated and fought back, seeing the scar on his throat. After a prolonged fight where Carter burned his hand on the stove and threw him out of a window, Demidov fled.
Returning to the Hotel Cosmopolitan to treat his injuries, Demidov informed his contact in Leviathan via the Remote Typewriter that Spider Raymond was dead and he still sought the Nitramene and Leet Brannis. Seeking revenge for his embarrassing defeat, Demidov also mentioned Carter and requested permission to execute her, which was granted. Demidov's contact then informed him that his next target would be a Mob Boss who Brannis would likely attempt to sell the Nitramene to.
Eventually, Demidov found the Mob Boss he had been sent to find. Demidov murdered the Mobster's wife and tortured him by plunging a knife in his hand before questioning him. The Mobster insisted that he had not wished to buy the Nitramene and suggested he ask Gino DeLucia. Once the mobster had been executed, Demidov sought out DeLucia who revealed the information he wanted before being executed as well, Demidov learned that Brannis would be at the residence of a Sheldon McFee.
- "This is where I get off."
- ―Peggy Carter to Sasha Demidov
Upon getting there, Demidov spotted Peggy Carter, Leet Brannis, and Edwin Jarvis leaving the place with a Daisy Clover milk truck filled with the Nitramene bombs. Managing to get ahead of them, Demidov leaped atop the truck and began firing to kill that inside, managing to dislodge the Nitramene and fatally wound Brannis while Jarvis fired a shotgun at Demidov in retaliation.
Carter got atop the truck as well and the two battled as Jarvis tried to use a shotgun to shoot him from inside, losing his key to the Hotel Cosmopolitan during the fight. Seeing a large body of water, Carter instructed Brannis to drive into the water; she took a knife and pinned the hand of Demidov to the truck, telling him that this is where she would get off. As the others jumped from the truck, Demidov went over with it; the truck then exploded and imploded, killing Demidov instantly.
- Expert Martial Artist: Sasha Demidov was highly trained in martial arts. Using weapons he was able to fight Carter for a while before she killed him.
- Expert Marksman: Demidov was accomplished in using firearms. He gained military experience as part of the Soviet Armed Forces. Demidov killed Spider Raymond without drawing the attention of trained Strategic Scientific Reserve agents in La Martinique.
- Expert Assassin: Demidov was able to kill multiple men with ease. Highly trained agent Peggy Carter was in an adjacent room and did not hear Demidov kill Colleen O'Brien in their apartment. Demidov tortured and killed Gino DeLucia, gaining information from a man in a profession known for discretion.
- Expert Spy: Demidov was able to infiltrate places and interrogate his victims without being noticed. Demidov entered Colleen O'Brien's Apartment without Peggy Carter noticing and he lived quietly at the Hotel Cosmopolitan without his landlord truly knowing him.
- Beretta 1934: The Beretta 1934 was Demidov's handgun and weapon of choice, customizing it with a suppressor for covert killings. It was the handgun he used to kill Colleen O'Brien in her apartment and in an attempt to kill Peggy Carter shortly after. He also used it to kill several mob bosses while tracking the Nitramene stolen by Leet Brannis.
- Spider Raymond † - Victim
- Peggy Carter † - Killer
- Colleen O'Brien † - Victim
- Mob Boss † - Victim
- Gino DeLucia † - Victim
- Leet Brannis † - Ally turned Victim
- Edwin Jarvis †
- Agent Carter
- The aliased which Demidov used in his passports were amalgamations of known filmmakers: