adjective
demonic
dee-MAH-nik/diˈmɑːnɪk/
Relating to demons or suggesting their evil or frightening power.
The creature's horns and claws give it a demonic appearance.

Etymology
Daimōn could name a guiding spirit rather than an evil being. Its use for pagan gods and unclean spirits in religious texts explains the sinister meaning behind demonic.
In context
more terrifying than mutation was abyssal demonization, common among abyssal demons or monsters eroded by demonic energy.
More examples
- A demonic figure haunted the story.
- The actor produced a demonic laugh.
- Their folklore described a demonic presence in the cave.
Forms
demonic
Similar words
- devilish
- Can sound mischievous rather than seriously evil or terrifying.
- diabolical
- Diabolical can describe extreme wickedness without literal demons.