Kaibutsu Ouji to Dokusou Tsukai no Himegimi

Only the princess can create the medicine that may save the man she loves. In an age of swords and conquest- Princess Lillie chooses to study medicine in a monastery before entering a political marriage to protect her kingdom. Meanwhile, in the neighboring kingdom, the king falls in battle and the crown prince vanishes without a trace. One day, a mysterious young man named Wolf appears before Lillie in shackles, carrying a small bottle of medicine. "I want you to make this." The medicine is made from Witch's Crown-a forbidden poisonous herb Lillie has been secretly researching. It becomes evident that Wolf is bound by a terrible curse that destroys his body in exchange for superhuman power. A fantasy romance between a cursed young man and the princess who may be the only one capable of saving him! (Source: BisouBisou Comics)