'Over the Wall' by Peter Wartman is an overlooked gem of a graphic novel. First published in 2013, its about time you acquainted yourself with it as the sequel 'Stonebreaker' is due out in June.
Anya lives in a village outside the walls of an ancient city, haunted by demons. Long ago her people lived there and performed wonders with the help of the demons, but the something went wrong and the demons rebelled - now taking all the memories of those they get ahold of. A barrier prevents the demons from escaping to the wider world, but as a rite of passage young men of the village must enter it to prove they are still masters of the city. Not all of the men return. Anya's brother has just failed to exit the city the night before and, even though her memories of him begin to fade because of this, she sets out alone to rescue him.
I loved the world building in this. Wartman's illustrations and spare text give a gorgeous picture of a whole civilization and culture - influenced by the Aztec and Maya - while hinting that this is only the beginning. Anya and the demon's relationship is playful and I look forward to reading more about it. Special order this one from your local bookstore if they don't carry it, you won't regret it.