Pity Kent or ‘replacement’ with this! (10)

I believe the answer is:

kryptonite

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'this' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'pity kent or replacement' is the wordplay.
'replacement' is an anagram indicator.
'pity'+'kent'+'or'='pitykentor'
'pitykentor' is an anagram of 'KRYPTONITE'.

'with' is the link.

Can you help me to learn more?

(Other definitions for kryptonite that I've seen before include "threat to Kent" , "Mineral avoided by Superman" .)

I've seen this clue in the Sydney Morning Herald.

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