Soredemo Sekai wa Utsukushii

Nike is a princess from the Rain Dukedom with the ability to control rain. After losing a game to her older sisters, she is compelled to marry Livius I, the ruler of the Sun Kingdom, who earned the title "Dreadful King" after conquering the world in three years. Upon meeting, Nike is surprised to discover that Livius, also called "Livi," is younger than her. He immediately demands she summon rain, and when she refuses, he has her imprisoned. Initially, their marriage is only formal, but over time, they begin to form a deeper emotional connection.