Dr. Faustus

Doctor Faustus' first appearance came in issue #107 of Captain America, where he attempted to drive Captain America insane. Faustus has a history of teaming with the notorious villain known as the Red Skull in plotting against Captain America.

Some of Faustus' notable events in comic history include: Creating the villain know as Grand Director, involvement with the villain (at the time) Moonstone, and death of S.H.I.E.L.D. agent Sharon Carter (which was later addressed that she, in fact, did not die).

Faustus was presumed dead for a number of years, but most recently appeared in Captain America #22, now living undercover as a S.H.I.E.L.D. psychologist, at the employment of the Red Skull. Faustus was given the task of manipulating Sharon Carter's mind into falling deeply in love with Captain America. Something which he proudly claims is his doing. During his time working for the Skull he treats him with almost no respect and frequently talks down to him. This behavior infuriates the Skull because usually speaking to him like this would  mean certain death for anyone but he can't have Faustus killed because of his importance to his plans.

It was also revealed within Captain America #25 that Faustus was responsible for manipulating Sharon Carter into assassinating Captain America.

Faustus also attempted to brainwash Winter Soldier to serve the Red Skull's purposes. When his methods of mental programming failed, he had planned to kill the Winter Soldier, only to have him escape due to an almost subconcious act of Sharon Carter, who was under Faustus' control. Faustus also brainwashed the Grand Director into believing that he was Steve Rogers so that the Skull could use him to help swing public opinion in favor of his candidate Senator Wright. After Sharon was stabbed by Sin and she lost the baby, Faustus betrayed the Skull and activated her S.H.I.E.L.D. transmitter before leaving the hidden base because he didn't want any of his creations to "fall into the hands of those monsters".