The Soul Society has been easily defeating Hollows for the past thousands of years. Now, the Hollows seem to appear less and less, and the Hollows that do appear are usually stronger than the average Hollow, some even being menos class. This has brought up suspicion within the Seireitei. Arrancar have also been appearing constantly, but seemingly doing no damage to others, and usually running when they see Shinigami. The Soul Society has been worried about the recent Hollow and Arrancar activity, even to the point of asking Vizards and Humans who can see them for help. They suspect that the Arrancar are planning something... something big.
