The legendary king of rock-and-roll (8)
I believe the answer is:
sisyphus
This might be a double definition.
'the legendary king' is the first definition.
The definition suggests a singular noun which matches the answer.
'rock-and-roll' is the second definition.
Both the definition and answer are singular nouns.
Perhaps you can see an association between them that I can't see?
'of' acts as a link.
Can you help me to learn more?
(Other definitions for sisyphus that I've seen before include "Greek doomed forever to roll a boulder uphill only to see it roll back down" , "Mythical king's" , "Legendary Greek king doomed to forever roll a boulder uphill" , "He kept rolling up" , "Greek king fated ever to roll a stone uphill in Hades" .)