The Laith Series

First edition of Clouded by Envy, old edition: 

Sometimes the very thing you wish for is your undoing....

Brenik has always been envious of his twin sister, Bray. Everything always came naturally to Bray, even after crossing through a portal from their fae world, while Brenik spent his time in her shadow. So, when Brenik discovers a way to get what he has always desired - to become human - he takes it. However, the gift turns out to be a curse that alters him in ways he never saw coming.

Bray can't help but be concerned for her brother, more so when he vanishes. While waiting for Brenik to return, she meets two brothers who realize she is not the least bit human. Her dark bat-like wings are proof of that. But somehow, an aching bond forms between Bray and the older brother, Wes.

When Bray reunites with Brenik, she finds an overpowering need for blood stirring deep within him. If Bray doesn't help Brenik put an end to his curse, it will not only damage those who get close to him, but it could also destroy whatever is blooming between her and Wes.

Perfect for fans of Holly Black and Sarah J. Mass.