Wyatt Earp, perhaps, following in darkness to stop urge evolving (10)

'wyatt earp' is the definition.
The definition suggests a singular noun which matches the answer.

'following in darkness to stop urge evolving' is the wordplay.
I cannot really see how this works, but
'following' could be 'f' (used when citing page numbers etc) and 'f' is found in the answer.
'darkness' could be 'night' (night is a period of darkness) and 'night' is found in the leftover letters.
an anagram of 'urge' is 'guer' which is located in the left over letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).

'perhaps' is the link.

Can you help me to learn more?