Which literary work, the character “Mephistophilis” is taken from?

Doctor Faustus, in full The Tragicall History of D. Faustus, tragedy in five acts by Christopher Marlowe, published in 1604 but first performed a decade or so earlier. Marlowe’s play followed by only a few years the first translation into English of the medieval legend on which the play is based. In Doctor Faustus Marlowe retells the story of Faust, the doctor-turned-necromancer, who makes a pact with the devil in order to obtain knowledge and power. Both Doctor Faustus and Mephistopheles, who is the devil’s intermediary in the play, are subtly and powerfully portrayed. Source: britannica.com