Bride of the Demon King by Viola Grace

Hiding from her demon lord has always seemed pointless, but she learned on the way. Now, she is ready to face him and her destiny.

She has worn a dozen names in her foster parents’ efforts to hide her from her demon lord. The name she used at the healer academy was Emrie, so that is how she set up her practice.
Tribute night was the demon lord’s birthday, and it was while she tended patients that she noted the time. She gets caught at a checkpoint and is forced to cover her presence with magic, but in her haste, she forgets one thing, her tribute.
Demon Lord Harrow has been looking for his mate with increasing urgency as the years have gone by. When he is looking over his tribute from the village of Neemin, he catches a familiar scent. He has caught this scent only once before, but he knows it. She is near. He confirms that the guards at the checkpoint came in contact with his mate, and then, he sets out to do what he has been longing for, claiming his bride.