Anger in hell -- prayers effective ultimately? (9)
I believe the answer is:
displease
'anger' is the definition.
(I've seen this before)
'hell prayers effective ultimately?' is the wordplay.
'hell' becomes 'dis' (I've seen this in other clues).
'prayers' becomes 'pleas' (plea is a kind of prayer).
'ultimately?' suggests the final letters (I've seen 'ultimately' mean this).
The last letter of 'effective' is 'e'.
'dis'+'pleas'+'e'='DISPLEASE'
'in' is the link.
(Other definitions for displease that I've seen before include "Aggravate" , "Nettle" , "Anger" , "Upset" , "Vex" .)