"Ceremonialist" and "Sacrilegious" achivements hint
To quickly unlock both achievements without replaying the entire game, save your game before you ascend the stairs to the ashes. During the scene, collect a pinch of ashes and put blood in the ashes. Allow yourself to be killed afterward and reload your save. This time, collect the ashes but don't put the blood in. Leave the temple and fight the disciples waiting for you to get the second achievement.