malefic [muh-lef-ik ]
1. Causing harm or destruction, especially by supernatural means.
2. Relating to the planets Saturn and Mars, traditionally considered to have an unfavourable influence.
There was a touch of spring in the air, a poisonous, malefic spring that seemed to burst from the manholes. (Henry Miller, Tropic of Cancer)
If by 'demon' you mean a malefic, supernatural creature, possessed of great powers, life span, and the ability to temporarily assume virtually any shape - then no. This is the generally accepted definition, but it is untrue in one respect ... It is not a supernatural creature (Roger Zelazny, Lord of Light)
On 5th November 2019, malefic Jupiter conjoined Saturn and the Dragon’s Tail (denoting viruses) in the house of pandemics. (Shashi Bhushan Dubey and A B Shukla, The way astrology views the coronavirus, Sunday Guardian, April 2020)
This tag deflects any malefic energy or entity from the person by drawing it into the bottle where bent pins, or nails, or nettles, traps it. When witch bottles are buried in the earth, it is believed that the maleficence will be drawn into the bottle and then committed back to the earth where it will be neutralized. (Jessica Ripley, How to Create a Witch Bottle for Protection)
'doing mischief, producing disaster or evil,' 1650s, from Latin maleficus 'wicked, vicious, criminal,' from male 'ill' + -ficus 'making, doing,' from combining form of facere 'to make, do'. *Online Etymological Dictionary)