He guides many an animal (3)
I believe the answer is:
cox
'he guides' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'many an animal' is the wordplay.
'many' becomes 'c' (C is the Roman numeral for 100**).
'an animal' becomes 'ox' (I've seen this in other clues).
'c'+'ox'='COX'
Can you help me to learn more?
(Other definitions for cox that I've seen before include "He's in charge of a racing boat and its rowers" , "Steersman" , "Helmsman" , "Passenger vehicle" , "Member of rowing crew" .)