Mephistopheles is the daimon bonded to Jedrek Tyler.
A portion of the Herald, Emily, was made using cells from "The Terminal Being". As Jedrek and Emily touch, these cells would enter Jedrek and affect the Daimones he eventually contacts. In simple terms, Jedrek's daimon, "Mephistopheles" has been altered by the Prophet.
Jedrek had always questioned his way of life - something that without doubt had a hand in awakening Mephistopheles, or "The Whisperer". Although exceedingly rare, when a potential incarnate host is broken spiritually or in mortal danger, the Daimones may initiate contact. Jedrek and Mephistopheles are an example of this very rare occurrence. But if another Daimones, the Prophet, had influence over the Daimones within Jedrek, this could explain why Mephistopheles was driven to initiate contact.
Above all, the Prophet needs Jedrek to defeat the Sovereign. The conflict between Jedrek's humanity and the destructive nature of his Daimones, the consolidation of the two by Jedrek's spirit... are these all part of the Prophet's grand scheme?
Mephistopheles is a demon featured in German folklore. He originally appeared in literature as the demon in the s goals”. 
Although Mephistopheles appears to Faustus as a demon – a worker for Satan – critics claim that he does not search for men to corrupt, but comes to serve and ultimately collect the souls of those who are already damned. Farnham explains, "Nor does Mephistophiles first appear to Faustus as a devil who walks up and down in earth to tempt and corrupt any man encountered. He appears because he senses in Faustus’ magical summons that Faustus is already corrupt, that indeed he is already 'in danger to be damned'."
Mephistopheles is already trapped in his own hell by serving the Devil. He warns Faustus of the choice he is making by "selling his soul" to the Devil: "Mephistophilis, an agent of Lucifer, appears and at first advises Faust not to forgo the promise of heaven to pursue his goals”. 
- ↑ (Krstovic, legend, and he has since appeared in other works as a stock character version of Satan.
- ↑ Farnham, Willard. Twentieth Century Interpretations of Doctor Faustus. New Jersey: Prentice-Hall, Inc.,1969: 6.
- ↑ (Krstovic, J. O. and Marie Lazzardi. “Plot and Major Themes”. Rpt. In Literature Criticism from 1400 to 1800. Ed. Jelena O. Krstovic and Marie Lazzardi. Vol. 47. Farming Mills, MI: The Gale Group, 1999: 202)