The Count's Daughter Avoids the Love Rival Scenario with Her Yandere Husband!!

One day, Sierra Zikitalis recalled the memories of her previous life. It turns out that she was reincarnated as the character that is used as the stalking horse* in an 18+ otome game! To escape such a troublesome role, Sierra decides to fall in love with a man who has nothing to do with the game. With the help of a spirit, she meets a handsome black-haired guy who is just the right guy for her... but it's not long before she realizes that the man she loves has a secret that could shake the world! --- Note: Refers to the side character that is used to test the main character's love.