Example : Devilish schemes.
The cold calculation and diabolic art of some statesmen.
The diabolical expression on his face.
A mephistophelian glint in his eye.

Synonyms : devilish, diabolic, mephistophelean, mephistophelian

Example : Something demonic in him--something that could be cruel.
Fires lit up a diabolic scene.
Diabolical sorcerers under the influence of devils.
A fiendish despot.
Hellish torture.
Infernal instruments of war.
Satanic cruelty.
Unholy grimaces.

Synonyms : demonic, diabolic, fiendish, hellish, infernal, satanic, unholy