Underworld ring has change of leader (4)
I believe the answer is:
hell
'underworld' is the definition.
(synonyms)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for hell that I've seen before include "'The road to . . . . is paved with good intentions'" , "Abode of the damned" , "Unpleasant place" , "Inferno" , "One of spelt out words" .)