The worst thing about the end of the world is we did it to ourselves. Isaac Thoma lived to see the last handful of survivors defeat the demonic champion. He is now alone, his past in ashes, the last and most powerful human on a blighted Earth. But what if he could go back?

Hurled back in time, Isaac has one chance to change it all. A chance to warn humanity of their impending doom. A chance to stop the [System] before shortsightedness and lust for power can render humanity extinct. Facing malign deities, demonic hordes, and the unstoppable march of human greed, Isaac will give his all to prevent the end that has already happened on the day the world became quantified.

To save the kingdom, he'll have to stop his own murder...

It’s hard to be a drunken idiot when the world keeps burning down around you. Cairn, the charming-yet-utterly-irresponsible heir to the Uskarrion throne, is all too happy to toss the crown aside. But an invasion, conspiracy, and rise of a terrifying villain result in his untimely death.

Then, Cairn reawakens. It's a decade earlier and he's in his childhood body. But he remembers everything...There's much to accomplish. First, however, he'd really love to stop himself from dying.