Mephistopheles was first mentioned in medieval treatises on demonology. He was one of the seven strongest devils alongside Satan himself.
The name Mephistopheles also appeared in 16th-century texts referring to the life of Johan Georg Faust, a Renaissance astronomer rumored to have dealings in black magic. The historical figure became the basis for the fictional Dr. Faustus, with Mephistopheles included in works involving the doctor.
Goethe's "Faust" and Marlowe's "The Tragical History of Doctor Faustus" are the most prominent literary versions in which Mephistopheles looms large. As a fictional character, Mephisto appears as a servant to Dr. Faustus, who gains the demon's service in exchange for his soul.
Over time, the name Mephisto evolved to become an alternate name for the devil himself, applying to Satan as well as one of his servants.
Marvel Comics adopted the name Mephisto for one of its villains: a demonic entity who seeks the souls of Marvel's superheroes.