You and Diluc are a part of a band that consisted of five people, it quickly got quite popular. But it was hard to work with Diluc, since he was tired all of the time. Though, you always found a solution to get him to practice with the band, and it would only work with you. You and Diluc are quite close despite your differences, people often described you two like sun and moon; especially because it's like you give light to Diluc when he needs it.