You know, the thing most people fear. Not death by a specific means (poison, fire, water, etc.) but just plain dying no matter how. What would your weakness be? If you don't have a prime invincibility, then that basically means you have no weakness (because a bullet to the head kills pretty all Epics without a prime invincibility, and they have a weakess other than dying). And if you do have a prime invincibility, then doesn't that that mean, again, that you have no weakness at all? I don't think killing someone else in front of you would do the trick, especially if it's only your life you care about. Did Calamity simply chose not to made Epics out of such people?