Engage for Princess

The White Provinces (Albion), once a unified nation established after conquering the indigenous beastmen and elves, had, after a long period of turmoil, split into the Red Dragon Kingdom, the Gray Wolf Kingdom, the Blue Octopus Kingdom, and the Golden Lion Kingdom, ushering in an era of four kingdoms. Princess Kerin of the Red Dragon Kingdom had her life saved three years prior during the War of the Underworld by the Prince of the Lake, who ruled the Dreamlands, and received a ring of oath from him. She is a knight princess who wishes to serve him. However, the prince was cursed after stabbing the Queen of the Night, and remains asleep in the Golden Lion Kingdom...?

(Source: Shounen Gahousha, translated)