Complex sentence: Doctor Faustus (real name Johann Fennhoff) is a Marvel Comics supervillain who has proclaimed himself the "Master of Mens' Minds," and is known for the use of psychological methods of combat.
Split into simpler sentences: Doctor Faustus (real name Johann Fennhoff) is a Marvel Comics supervillain. He has proclaimed himself the "Master of Mens' Minds," and is known for the use of psychological methods of combat.