Cards that benefit from having fiends in your graveyard
Dark Necrofear requires you to remove 3 fiend type monster in your graveyard to special summon. You can speed up the summon by using the effect of Fiend Griefing to send fiends to the graveyard.
Archfiend Empress can negate the destruction of any dark fiend monster on your field except itself, but only if you remove a dark fiend monster in your graveyard from play. Use Fiend Griefing to help fuel this effect. Additionally when destroyed it can revive a level 6 or above dark fiend monster in your graveyard except Archfiend Empress.