They're bent on being bad (6)
I believe the answer is:
crooks
If this is the answer I cannot explain how the clue works.
Can you help me to learn more?
(Other definitions for crooks that I've seen before include "taken in hand by bishops" , "at 16 down [MAN UNITED]" , "Rustlers" , "Criminals and bishops' staves" , "shepherds lay hold of" .)