Evil spirits taking part in demonstration (6)
I believe the answer is:
demons
'evil spirits' is the definition.
(demon is a kind of evil spirit)
'part in demonstration' is the wordplay.
I cannot quite see how this works, but
'part' could be 'mons' (mons is a kind of part) and 'mons' is located in the answer.
The remaining letters 'de' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'taking' is the link.
Can you help me to learn more?
(Other definitions for demons that I've seen before include "Fiends or devils" , "Evil spirits, devils" , "Wicked people" , "Evil supernatural beings" .)