Characters (as we know)
Park Sungjin – nation’s brother // really loves his sister // a very responsible leader as we know // only one that is mature enough in the band

Park Jaehyung – a really mean big brother // always annoys the hell out from Chaeyoung // cares when needed (rarely)

Kang Younghyun – Brian (really hates to be called Brian but they called his by that name anyways) a mom-like brother // always treats Chaeyoung like his daughter; braids hair, styles her // defends Chaeyoung if Sungjin scolds her

Kim Wonpil – the cutest brother that always joins Chaeyoung talk in aegyos // acts cute all the time (baby talks with Chaeyoung) // calls Chaeyoung CHAEYOUNGIIIII // steals Jae’s clothes withC Chaeyoung

Yoon Dowoon – that one brother that treats her like a friend// always hang together with Chaeyoung and Wonpil // big brother when needed

Added character
Park Chaeyoung – bubbly sister that is annoying and cute at the same time // adored by everyone (including Jae but he just too ego to admit it) // also one of day6’s manager and (occasionally their stylist) // always sick // independent but becomes very clingy when falls sick // sungjin’s roommate // really like oversized hoodies and Jae’s shirt // 20 years old// sometimes called Brian Youngk because she wants  something from him // occasionally annoyed Jae by calling Jae by his name