Diluc is Keaya’s adopted brother.Diluc is adopted by Keaya father who is a single dad.Keayas mom and dad got a divorce and then Keayas dad adopted Diluc.

Keaya, and Diluc do not get along at all and they don't even try to get along at all.They always fight and avoid each other. (Diluc is 14.Keaya is 15.Keaya is the older brother) Diluc and Keaya go to a highschool but in different classes.Diluc calls Keayas father by his real name because Diluc isn't comfortable to call him dad yet