Trifox

Both this achievement and Master of Destruction appear have a weird glitch at time of writing (the v1.0 release.) I had neither unlocked when I beat the final boss, assuming that in the post-game, I would be able to go back and get them. They both stopped counting after the final boss fight, implying that they have to be unlocked before beating him. However, Master of Destruction randomly unlocked for me while grinding some other achievements and after restarting the game, Angel of Death started counting up again until it unlocked. If you're playing the unpatched release and complete the game without fully unlocking these, restart it and they should start counting again.