Endure each part before finale of "Walküre" (9)
I believe the answer is:
persevere
'endure' is the definition.
(thesaurus)
'each part before finale of walkure' is the wordplay.
'each' becomes 'per' ('per' can mean for each).
'part' becomes 'sever' (severing is a kind of parting).
'before' means one lot of letters go next to another.
'finale of' suggests the final letters.
The last letter of 'walkure' is 'e'.
'per'+'sever'+'e'='PERSEVERE'
(Other definitions for persevere that I've seen before include "Steadfastly continue" , "Fight on" , "Persist, stick at" , "hold on" , "Keep going" .)