Hime to Inyoku no Testament

In Winstol Kingdom's dark province of Woodfall— A land where ominous clouds have sealed the sky, devoid of sunlight for a whole century, feared as a "cursed realm" forsaken by the gods, is governed by the so-called "Monster Lord," Gran Woodfall. Secluded in a timeworn castle deep within an enshrouded forest, Gran is a bona fide monster, unaging due to a curse, who has lived for a century. Summoned to this lair of monstrosity is Princess Sylphia of Winstol, offered as Gran's bride-to-be as per an unholy pact between him and the King of Winstol. She is the "cursed princess," confined to the royal castle for carrying a calamity-invoking curse since her youth. But that very curse is the key to…