Thus see in action monster-slaying hero (7)

I believe the answer is:

theseus

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

'thus see in action' is the wordplay.
'in action' indicates an anagram (I've seen this in other clues).
'thus'+'see'='thussee'
'thussee' anagrammed gives 'THESEUS'.

'monster-slaying' acts as a link.
I am not very happy about this link. It may belong to another bit of the clue.

Can you help me to learn more?

(Other definitions for theseus that I've seen before include "Duke of Athens (AMND)" , "Athenian king" , "Mythical hero" , "Heroic figure" , "classical hero" .)

I've seen this clue in The Telegraph.

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