Johann Fennhoff is a psychiatrist and a member of Leviathan.
Johann Fennhoff helped many wounded soldiers during World War II. Because of its ability Leviathan decides to capture him. He was reluctant to join Leviathan but when he saw how they killed a man for refusing, he decides to join them to save the life of his family.
Three years later, Fennhoff called himself as Ivchenko. When Peggy Carter, Jack Thompson, and the Howling Commandos had infiltrated the Red Room Academy, he posed as a prisoner of Leviathan. After being released by Carter, Thompson, and Howling Commandos, Nikola went crazy and took hostage Happy Sam Sawyer; Ivchenko then shot and killed his cellmate. Having escaped from Leviathan's soldiers, Dugan gave to Ivchenko bottle of whiskey that Peggy had given to him. Ivchenko met with Chief Roger Dooley after arriving in the United States.
A day later, Ivchenko and Dooley met again; at this meeting tries to hypnotize the Chief without success. Later, Sousa informs Dooley about Carter's true alliance, Dooley then orders Yauch to take of Ivchenko as he was the star witness of the SSR against Howard Stark. Ivchenko got to know the different evacuation points after hypnotized Yauch. As a final instruction Ivchenko ordered Yauch to commit suicide. Shortly after, Carter saw Ivchenko was communicating with someone in another building.
After Carter confessed to Dooley the reasons why she helped Stark, the Chief then sent agents to arrest the person who was in the other building; while he was in charge to arrest Ivchenko. Dooley was hypnotized by Ivchenko before he could arrest him. Dooley then locks Jarvis and Carter in a room at the request of Ivchenko. Already uninterrupted, Dooley gives Item 17 to Ivchenko. Before leaving, Ivchenko asked Dooley to put the Self-Heating Vest as a last instruction. Later, he and Underwood went to a cinema to test Item 17.
Underwood and Ivchenko drove as they discussed what to do with the Midnight Oil. Suddenly, a police officer stopped them by a traffic light have passed, Underwood was ready to kill the officer but Fennhoff told her not to attract attention. She then used her innocent person to convince the officer; however the officer received a call describing Underwood and the car perfectly; the officer turned and watched as Underwood was pointing at him with a gun. Fennhoff and Underwood went to a warehouse of Howard Stark and he heard on the radio that Howard Stark returned to the United States. Fennhoff told Ivchenko that they should return to the city and kidnap Howard Stark. He hypnotized Officer Pike and used him to bring Stark to him before returning to the hangar.
The plan was a success and Stark was brought before him. Fennhoff told Stark why he hated him and how he take revenge on him. Fennhoff managed to brainwash Stark into believing he was going to save Captain America; so that he would deploy Midnight Oil over Times Square. Fennhoff flees when Agent Carter arrives at the warehouse, allowing Underwood and Carter will fight each other. Fennhoff tried to brainwash Sousa and make him kill Agent Thompson; Sousa pretends to be hypnotized in order to arrest the psychiatrist. Fennhoff was knocked out and arrested by Sousa and Thompson, with a piece of cloth in his mouth to stop him from speaking.
Fennhoff was to jail and kept muzzled to prevent him from speaking. There, he met his cellmate, who was a great fan of his work. He listened as Zola told him that it was good that he was in an American prison, as America was the land of opportunities. Zola then gave him a pencil and paper so they can communicate.
- In the comics, Dr. Johann Fennhoff was brilliant psychiatrist who took the codename of Doctor Faustus.