If you mean those who are slaughtered in Hell, well, unless you take certain precautions, they regenerate. Could take a few days, a few weeks, or even months depending on how they "died" in Hell. The only way to permanently kill a Sinner in Hell is via angelic magic or weaponry.

And when killed that way, well, we go to the void. And what happens there, no one knows.

[He chuckles.]

It's Hell, my dear. It's the ultimate prison for those who commit heinous acts. It's supposed to be a "cycle of misery". I knew exactly what was waiting for me when I killed that first time: It only takes one mistake to damn someone for eternity.

[Which was why he'd chosen to just keep killing, targeting those like him: He was already damned, so why not?]