User blog comment:RoyalGuard-Elite/Asauchi/@comment-4690655-20130204215938

Well it might be similar to how an Arrancar's zanpakuto works, that is what an Asauchi truly looks like but Oetsu could possibly seal it into a sword form before giving it to the Shinigami, and the reason the Royal Gaurd doesn't have their zanpakuto on them is because they just don't see the need to carry it on them at the moment, and when Senjumaru showed those spheres and one of them had Tensa Zangetsu in it, I think that they have some way to shrink themselves so that it can be transported with ease and from what we've seen, she was with the rest of the Royal Guard the entire time