Bound and Tide by A. K. Caggiano

Xander Shadowhart’s mother is dead. Well, no, not exactly—nothing could probably kill Birzuma the Blasphemed—but she is banished to the infernal plane, and that’s almost as bad, especially considering she seems to have taken Xander’s control over his powers with her.
Born to a demon, Xander’s purpose has been beaten into him his entire life: serve his maker and carry out her will, but when the time comes to summon his mother back into the material realm, he’s not exactly sure he wants to…er, is able to, not without mending his command over the noxscura first. As luck and plot would have it, though, he’s in possession of a decades old clue that just might teach him how.
But quests always have their interruptions, and when a haughty herbalist refuses to give him the attention he deserves, Xander becomes distracted, especially when her threats and demands awaken in him a new desire to serve. He can’t be blamed, not when she’s so beautiful and so talented and so mean, but the piling on of newly discovered kin and complications with his arcana jeopardize everything: his connection to his dark powers, his plan to bring his mother back, and, most horrifyingly, his feelings.

Blood mages aren’t really supposed to have those, but it may finally be Xander’s turn to learn what the rest of us have known all along.