Like Nero, he could destroy much of Rome, perhaps (7)
I believe the answer is:
emperor
'like nero he could destroy much of rome perhaps' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'like nero he could destroy much of' is the wordplay.
I cannot quite understand how this works, but
'he' could be 'em' and 'em' is present in the answer.
'of' could be 'o' and 'o' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for emperor that I've seen before include "Sovereign - ruler" , "eg Nero" , "Penguin of largest known species - a great ruler" , "He rules over several states" , "Title of sovereignty" .)