/MOAR
[He hesitates, no sip of coffee to distract from it this time.]
[When he finally speaks, it's with a soft reverence,] When a human is grieving the loss of a loved one, the Earl appears and offers a chance to be with the departed once more. If the human agrees, the Earl brings the departed soul back -- but as an Akuma. A weapon powered by a human soul that does his bidding. Their blood is deadly to humans.
[He looks as if he's going to say more, but that should be sufficient. No one needs to know the full extent, it would just be needlessly cruel to tell it.]
Innocence purifies the souls of Akuma and lets them rest. If they were to be killed by any other mechanism, the soul wouldn't be saved.