adjective
demoniac
dih-MOH-nee-ak/dɪˈmoʊniˌæk/
Like or relating to an evil spirit.
The mask has demoniac horns and glaring eyes.

Etymology
Possession by a demon broadened into anything like or relating to evil spirits.
More examples
- The story describes a demoniac figure at the gate.
- A demoniac face was carved into the prop.
Forms
demoniac
Similar words
- demonic
- Is a common adjective for relating to demons.
- diabolical
- Can suggest extreme wickedness without a literal spirit.