Dies following underworld disposing of leader (5)

I believe the answer is:

fades

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'dies' is the definition.
The answer and definition can be both related to change as well as being verbs in their -s form.
Maybe there's a link between them I don't understand?

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for fades that I've seen before include "Loses colour or freshness" , "Gets less" , "Loses colour, through age or sunlight" , "Gets weaker" .)

I've seen this clue in The Independent.

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