Falling in love with the devil.

Metaphorical book about a female (the angel) falling for a toxic boy(the devil). They're not actually religious figures like the angel or the devil, they're ordinary beings but the metaphor is kept throughout the novel to emphasise the girls goodness and the boys toxicness. Though they are both in such different aspects they seemingly attract to this forbidden love, although the love feels so right it is painful. Though they both want to let go they can't and they'd jeopardise anything for they're relationship sake. Eventually the angel decides that feeding in this poison called love would get her killed, so she let's go.