Sage Derby ruins Cheshire lying in the middle (5)
I believe the answer is:
rishi
'sage' is the definition.
(term for a Hindu sage)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for rishi that I've seen before include "Revered man" , "holy man" , "Guru" , "Spiritual leader" , "wise man" .)