(The original Adam Redemption/Adam Agenda fic)
After the last extermination, Adam survives but is cast out of Heaven and sent to Hell. Charlie encounters him and learns there's more to the story she was told growing up. Adam wasn't always the villain he was portrayed as and her parents weren't the heroes she believed them to be.
This is the story of Hell told by the man who used to have everything. And his tragic downfall where he lost paradise not only once, but twice.
"Lucifer could still remember the first time he’d seen Adam. Vividly. It was one of those memories that never quite seemed to fade. That tilted its head up in defiance at the cruel hand of time and stood its ground, refusing to be dulled by something so trivial as eternity.
He had been beautiful."
or
An AU where Adam and Lucifer knew one another a bit more intimately during their time in Eden (and what comes after).