He struggled to maintain faith in the past (8)
I believe the answer is:
crusader
'he struggled to maintain faith in the past' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he' is the wordplay.
I cannot quite understand how this works, but
'he' could be 'der' and 'der' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for crusader that I've seen before include "religious zealot" , "Religious campaigner" , "What Simon de Montfort became" , "Earnest campaigner" , "Vigorous campaigner" .)