Crimson Spell vol. 2 (Yaoi manga)

Prince Vald is a proper, honorable swordsman by day and a sensual, insatiable demon by night. The only one who knows both faces of the cursed prince is his traveling companion, the sorcerer Halvi. During the day the handsome sorcerer keeps an aloof facade even as he sates the demon’s desires nightly. However, Halvi finds he is starting to feel a deeper bond with the young prince. Meanwhile, enemies who want Vald for themselves are beginning to make their move.