Well judging from the size of the shinagami shown in ch 448, I thought it was a guy. I guess cus it was ''zoomed in'' drawing, the shoulders being broad and feet looked like a male's. But reading on other forums, most ppl r saying it's Rukia or Karin, I still have my doubts. Anyways for me it's hard enough to guess bw the gender, let alone the identity of the shin.