User blog comment:Xilinoc/Ch. 533 Everything but the Rain op. 6 - "The Gravitation"/@comment-4207271-20130411122953

Aizen might have made a Quincy-based Hollow after this, and since he knows of Masaki, maybe when she is killed he uses her soul to make a new hollow, and kept it as a last resort weapon, in case Hogyoku and the Espada failed? Perhaps Juha knows and wants it as a weapon himself, so needs Aizen to get it?