I won this through a contest on Booklikes. It looked interesting, but I didn't enjoy it all that much.
Ruin is the hero. He seems to just come to exist in the swamp one day. He knows things, but not really. It turns out he's a "carnificem". A type of angel and it seems like he's reborn periodically, although that is not specifically stated. He's also referred to as "woe". He has a bunch of tattoos that are like a "keyboard" for navigating to the people he is supposed to judge and execute.
Isadora is the heroine. Ruin watches her from afar for a couple of days and interrupts as an ex-boyfriend is about to rape her. Ruin feels tied to Isadora for some reason. She is supposed to be super smart and a scientist. She's quite the contradiction. She's attracted to Ruin and gives him several books (encyclopedia, medical text, etc) to help educate him. Her scientist background is mentioned many times in this early part of the book. Then, she lets him finger her to orgasm and gets pissed off when he won't fuck her. The next day, when he wants to fuck her, she's suddenly a "Christian woman" and won't have sex outside of marriage and without love. This leads to Ruin reading her bible and going to church with her. They begin having debates about religion. It just becomes ridiculous.
And it ends in a cliffhanger. Luckily, I'm not interested in continuing.