Yuki is the pierced and rebellious twin who breaks all the rules and does whatever she wants. She's a good person deep down, but she doesn't like playing by the rules. And she's always up for a new adventure and challenge. While Yumi is the quieter and more docile twin. She likes to play by the rules and does everything by the book. She has a good job and a stable lifestyle, but she's always looking for something more. She's not as wild or daring as her twin Yuki.