How to create credible demon names for dark fantasy
Demonic names in literature and games typically have harsh consonants (z, x, kh, th) and rotund endings evoking arcane rituals. Mephistopheles, Beelzebub, Asmodeus are canonical examples: three to five syllables, mixing stop consonants with sibilants, sounding ancient without being easily pronounceable. Your generator can emulate that pattern by combining a short prefix with a thick suffix.
A useful technique: include apostrophes to suggest unpronounceable true names. Bal'gor Vornath, the Soul Devourer suggests the full name is only an approximation of something more sinister. In D&D, major demons have 'true names' whose knowledge grants summoning power, while common names are public titles.
Avoid names that sound human or too phonetically English. Bobby the Demon immediately breaks tone. Also avoid the opposite trap: piling consonants until the name becomes unpronounceable. Khrzthrgxoth is noise, not a name. Practical rule: you should be able to read it aloud smoothly even if it sounds strange. Three distinguishable syllables with a strong epithet work better than ten piled syllables.
Literary traditions: from Dante to modern fantasy
Dante Alighieri in Inferno organized demons in specific hierarchies and geographies: the Malebranche guard the corrupt's pit, each with individual name (Malacoda, Scarmiglione, Calcabrina). This tradition of individually naming sub-devils influences D&D: archdemons like Demogorgon, Orcus, Graz'zt have distinct biographies and domains, not interchangeable.
Milton in Paradise Lost popularized names like Belial, Mammon, Moloch, each with precise theological personality. For modern fantasy this offers three useful registers: classic biblical names for major demons, inventions with arcane suffixes for subordinates, and descriptive titles for anonymous horrors. Doom Eternal and Diablo use this layer to differentiate enemy beasts from antagonists with narrative.
In contemporary literature, Jonathan Stroud's Lockwood & Co. trilogy uses technical classificatory names for ghosts and entities, avoiding traditional gothic. If your work has bureaucratic or official tone, you can mix archaic nomenclature with modern classifications: Class IV Entity: Marb'agor of the Outer Ring. That mix creates worlds where the demonic is object of study, not just threat.
Frequent mistakes when naming demons in novels and games
First mistake: using the same register for all demons. If both the supreme archdemon and the minor demon appearing on page three share name structure, the reader loses hierarchical sense. Reserve elaborate names for important entities; use short functional names for anonymous horrors. Drak works for combat enemy; Astaroth Vornath, the Three Crowns should appear once and leave a mark.
Second mistake: copying too much from Christian mythology without recontextualizing. If your world doesn't have Christian God, calling the villain Lucifer creates dissonance. Better invent names that evoke the demonic without appropriating the religious framework. Gaiman's Sandman handles this with elegance: uses traditional names but reinterprets them within his own mythology.
Third mistake: ignoring the demon's domain. Each entity should govern something (lies, desire, oblivion, war) and its name or epithet should suggest it. Vex Phaeris, Torment Weaver suggests his power is mental, not physical. That specialization prevents your demons from being interchangeable and gives texture to your cosmology.
Adapting names to styles: epic, gothic, technical
For classic epic fantasy (D&D, The Wheel of Time), use bombastic names with hard consonants and arcane suffixes. Mal'gar Drogul, Prince of Discord, of the Molten Iron Throne immediately establishes hierarchy and domain. These names work in solemn reading, especially when a character pronounces them in ritual.
For gothic horror (Lovecraft, Poe, Shirley Jackson), prioritize suggested unpronounceability and names that seem transcriptions of non-human sounds. Khaal Zerith is more sinister than Demogorgon precisely because it doesn't conform to familiar phonetics. In this register, descriptive epithets reinforce terror: 'the One Who Waits Sleeping', 'the Form Without Color'.
For modern technical or occult tone, mix classic names with scientific classifications. The Magnus Archives and Welcome to Night Vale use bureaucratic jargon to frame the supernatural: 'Category 7: Beleth Marax, Custodian of Forbidden Codices, jurisdiction of the Pit of Black Blades'. That fusion of registers creates distinctive tone where the demonic is real but domesticated by human documentation.