Board Thread:General Discussion/@comment-9991778-20130601230059/@comment-7472785-20130622073751

Sisters, foster sisters, half-sisters, step-sisters, sorority sisters, clan sisters - did we already mention all possibilities?

Another side note - as in these animated series the characters are generally ageless, and if we assume that the swelling of boobs is not a sign of age, who says that Yang automatically is the older one?

Although, generally speaking, I believe that age will not be an issue among the four - maturity might though.