User blog comment:Lia Schiffer/423: Farewell Swords/@comment-3041141-20101008035850/@comment-28861328-20101009011159

Hollow powers are part of his Shinigami powers, hence why the Hollow Tensa Zangetsu was said to represent the whole of his spiritual power. If Hollow Ichigo had remained after Ichigo lost his power, Ichigo would have turned into a Hollow almost immediately after using Mugetsu.