I Became King by Following My Little Sister’s Advice. Now the Princess I Forced to Marry Is Giving Me Death Stares, What Should I Do?

In a world of empires and kingdoms, a demoted protagonist receives unexpected advice from his little sister, leading to a chain of events that sees him become a king and forced into a marriage with a princess. As the tension between them grows, he must navigate the complexities of power, love, and loyalty. Will he succumb to the princess's death stares or find a way to mend their relationship?