Em Shimizu

Il-Ruen Okarzad has been caged all his life in a backwater castle overlooking a quiet little pocket of the empire: far away from the intrigues of the capital, the turmoil of the borderlands, and every last one of his scheming, backstabbing relatives. It is not an unpleasant life, and though Ruen has every reason to resent his position, he fritters away his days in peace, haunted only by the vaguest sense of dissatisfaction.

That is, until one winter, a magical accident unleashes Ruen's long dormant powers -- much to the dismay of his family, who've been trying to keep him out of the already complicated line of succession. One enterprising aunt, taking advantage of the ensuing drama, sends her demon servant to Ruen so that he might be taught how to harness his newfound magic. But the demon is the most beautiful woman Ruen has ever met, and he's far more interested in bedding her than in learning his lessons...

Still, no contracted demon with any sense of pride has ever failed in the duties set by their master. And if Ruen's to survive the long winter, he'd better learn fast.