Seijo Mellia to Sennen Oukoku no Kishi
聖女メリアと千年王国の騎士
A girl named Mellia, unable to use magic, was orphaned at a young age and later placed in a cruel home. Struggling with feelings of worthlessness, she meets Douglas, a knight serving the royal princess. He is searching for a magical substance that might cure the princess's sickness. Their meeting marks the beginning of a story centered around a vow spanning a thousand years.