Ruler said to have played with fire (4)

I believe the answer is:

nero

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'ruler' is the definition.
(I've seen this before)

I don't understand how the rest of the clue works.

(Other definitions for nero that I've seen before include "Roman emperor who fiddled while Rome burned" , "Emperor, 'burnt' Rome" , "Barbarous Roman emperor" , "He's reported to have fiddled while Rome burned" , "Roman tyrant" .)

I've seen this clue in The Globe and Mail.

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