You're the woman going by Sis Strider. [Dirk mentioned you to her. And since you mentioned him being Dirk's brother, it only made sense. He wouldn't know who else would refer to him as that, anyways.] Your some Dave's older sister. [He says that fairly loosely. He can't fathom why she isn't both Dave and Dirk's sister.]

How come you don't also have a second brother?