The phrase "a fiend of" is correct and usable in written English.
It can be used to describe someone who is a strong enthusiast or supporter of something, often with a negative connotation.
Example: "He is a fiend of video games, spending countless hours immersed in virtual worlds."
Alternatives: "a fanatic of" or "an addict of".
She was a fiend for problems of sequence and logic.
I became a fiend for them, eating upwards of five a day.
But a close fiend of Tynan, Unison official John Lambie was a member of the secretive selection panel and is believed to have backed him.
Underneath the fantasy trappings that have been a franchise staple since that first zombie slowly turned and stared right through you, there's always been a human element to the antagonism Umbrella wasn't founded by a foul fiend of the undead variety, after all.
Robert Christgau characterizes Scott-Heron's original narratives as those of "a drug fiend of considerable perversity and tremendous intelligence who's gonna be dead soon", and comments that Jamie xx "hears in [Scott-Heron's] last testament an irreversible disintegration that he translates into heavily sampled minimalist electro marked indelibly by Scott-Heron's weariness, arrogance, and wit".
She was drawn to these passages now, but when she read them she found that what she had pounced on with such satisfaction, at one time, on rereading seemed obscure and unsettling.... what to the partial vision of the living appears as the act of a fiend is perceived by the wider insight of the dead to be an aspect of cosmic justice...
Surely it was a fiend in the likeness of the god that ordered this! Seated on the holy tripod?
Sam Farber, who was spurred by a fiend in the form of a vegetable peeler to start Oxo, the housewares manufacturer whose ergonomic rubber handles grace its kitchen utensils in many homes, died on Sunday in East Meadow, N.Y.
Nick Zinner's guitar-playing remains nervy and hostile, laden with as many effects as exist in the guitar shop, while Brian Chase, looking solemn and professorial, but drumming like a fiend, supplies the kind of versatile beats that span art-punk and synth-pop (he does jazz in his spare time).
If the sending is not performed, the body's spirit may remain trapped in the physical plane and take on the form of a fiend.
