User blog comment:Lia Schiffer/425: A Day Without Melodies/@comment-2045702-20101103044640/@comment-1248963-20101103052039

The shadow seems odd, but I do believe it's Byakuya. The top of his head is too straight, so it matches the Kenseikan. His neck shows something that could resemble the scarf. And his way of speech is very formal, and calls Ichigo by his full name, something few other characters do. I was unsure too, but I don't think it could be anyone else but Byakuya because he's one of the most important people to Ichigo in the Soul Society and one who has pushed him to get stronger. Ichigo got Bankai because he wanted to defeat Byakuya, that's how important he is.

There could be other people who could be considered important to Ichigo in the SS, like, say, Kenpachi, but the shadow or the speech pattern don't match at all. So I don't think it can be anyone but Byakuya