The Space Between by Brenna Yovanoff

Daphne is the half-demon, half-fallen angel daughter of Lucifer and Lilith. Life for her is an endless expanse of time, until her brother Obie is kidnapped—and Daphne realizes she may be partially responsible.

Determined to find him, Daphne travels from her home in Pandemonium to the vast streets of Earth, where everything is colder and more terrifying. With the help of the human boy she believes was the last person to see her brother alive, Daphne glimpses into his dreams, discovering clues to Obie’s whereabouts. As she delves deeper into her demonic powers, she must navigate the jealousies and alliances of the violent archangels who stand in her way.

Books that are linked to hell in some way are very fascinating to me, whether its the hot, firey place, a place for lost souls, Hades's underworld, Lucifer's playground, whatever the case may be. Did you ever notice that not many people touch on Heaven and what it's like in YA. If you know of a book - send it my way. 

Anyway - Daphne is a character that just doesn't fit in with Lilith and Daphne's soul sucking sisters. She's not a temptress and the only person who gets this about her is Obie. And while she doesn't understand the women of her family, Obie's ways and feelings are very strange to her. She doesn't understand how he could turn his back on the underworld to stay above ground with a human. 

But then Obie disappears, Lilith freaks, and Daphne finally goes above in search of Truman, a guy who has dreamed of Daphne. Truman is Daphne's ticket to Obie. 

Truman is my favorite character in this. He's not your typical leading male protagonist. In fact, he's kind of broken. He's a fixer upper and Daphne can't stay away from his problems which side track her from her mission.