The Silence Shatters

''Before the events conserning Aizen's betrayal, in the Turn Back the Pendulum arc, there was an evil stirring within Seireitei, unnoticed by the public. Kurei Yuzu, a shinigami who awakened the whole world of Shinigami by shock in his illegal researches, was taken in and was locked inside the Maggot's Nest, or so they thought.''