Having not been sealed since the Sage himself summoned it, it was not yet up to it's full power, and for the shinobi world itself, that was a blessing. One day, the Helixian Clan Leader made a decision to divide it and seal it in the Helixian Clans Chamber of Sealed Forbidden Scrolls and after a few days of preparation, they went through with it. They separated Kryonosis' soul from it's body and then divided it's skeleton into 3 sections, sealing each section in a separate scroll. Then they sealed it's soul in a separate scroll as well, so that at some point in time, a Helixian could unseal and tame it at last.