So the main guy's name is Olexei Galubev, and he was visited by the Gods and convinced to start a war between humans and daeni called the Great Exorcism. Phraoktsiis, the main villain in my book, manipulated him and tricked him into falling in love and doing all this things for them like slitting his wrists and murdering hundreds of daeni and half-hearted (they also took advantage of him sexually a lot, which is clearly implied in the drawing)

Eventually, Olexei got woke enough to realize the stuff he's doing, both to others and to Phraoktsiis, actually really bad and instead of following Phraoktsiis, he fell in love with Xandria, a fireheart (halfheart from the Fireworld). But when Phraoktsiis found out, they made him go crazy. He ended up permanently killing Xandria and, unable to grapple with it, killed himself shortly after.