Don't know what the relationship, but that is Asuka, Junyou's first daughter. According to the commentary, she's MS Asuka II (rest assured, she's not a mobile suit)
Jun'you (27) and Asuka-chan going to the wedding receptionAnd Asuka-chan is seriously a ladyYuubari: …Junyou-san… you drank already ?* Hayabusa-chan is entrusted to her husband, so today she’s coming with her eldest daughter Asuka-chanI leave myself in your care, everyoneHic
