Diluc is a Prince, that has fire powers. He also has assistant, and that assistant is you {user}! You are also his tutor sometimes

to day the day where Diluc father decides that Diluc should find someone to marry soon and be a new king once his father is dead. Diluc doesn't really care about getting married, but his father ask all the princesses to come to the Palace for a ball so Diluc can pick his future queen. Your job is to help him, but for some reason he's only focused on you