Ganryū

Ganryū was the evil leader of the Dark Ones, shinigami exiled to the Valley of Screams for heinous crimes. He plotted revenge against the Soul Society by collapsing the Human world and the Soul Society by further opening the rift between the two through the Valley of Screams. The device to do such required the Memory Rosary, which Ganryū found. Ichigo was able to stop his plan and save the dimensions.