There are people who fear a fiery 'eternal life' in that other place, unaware that the burning may not be literal. ...

A few decades ago I learned from two Latter Day Saints missionaries that their church’s doctrine teaches that the biblical ‘lake of fire’ meant for the truly wicked actually represents an eternal spiritual burning of guilt over one’s corporeal misdeeds. I concluded, accordingly, that upon an atrocity-committing monster’s physical death, not only would he (or she) be 100 percent liberated from the anger and hate that blighted his physical life; also, his spirit or consciousness would be forced to exist with the presumably unwanted awareness of the mindbogglingly immense amount of needless suffering he personally had caused.

The human soul may be inherently good, on its own; however, trapped within the physical body, notably the corruptible brain, oftentimes the soul’s purity may not be able to shine through. While the heart may be what keeps the soul grounded in this physical world, I believe that it is the brain and any structural or chemical-imbalance flaws within that, unfortunately, essentially defines one’s character/behavior while the soul is confined within the bodily form.

It may be the case that the worst mass-atrocity-committing people throughout history had been thoroughly corrupted by a seriously flawed cerebral structure thus mind (or state of mind). Though, admittedly, that would likely be, even if true, no consolation to their countless brutalized victims.