Secrets of Alkrose (Alkrose Academy #2) by K.M. Moronova

Wicked things are happening at Alkrose Academy.

Terra, Finn, and Edgar have finally reunited, but nothing is as they hoped. Terra's beloved Raine has been blighted by her untrained powers, a fate that spells his ultimate demise. As they scour the academy for anything that might save him, they uncover secrets lying in the dark. Secrets that involve Elias, Arthur, and the formidable Headmaster Emerai.

Meanwhile, the students prepare for the mysterious second-semester exam, rumored to be a harrowing assessment even deadlier than the Culling. If they can survive until then, that is-some Shadows are more bloodthirsty than others.

Only the elite will survive.

Face death boldly.