Koi no Hate Made, Yoru Yami no Oni Sarawarete

Princess Lunaphilia, who has been treated poorly since childhood due to a leg problem, is forced to marry the tyrant of an enemy country. Though she feels reluctant, Lunaphilia tells herself that it is selfish for someone like her to want to freely choose her own path, and the day of her departure arrives. However, before she can reach the enemy country, she is kidnapped by Cain, a monster feared by the people as the "King of the Night." This is a fantasy story about the love between a demon king whose love is too intense and a lonely princess. https://www.cmoa.jp/title/342524/