Hollow Manifestation

 is a technique used by the manifested spirit of Kōga Kuchiki's Zanpakutō, Muramasa.

Description
The Hollows which Muramasa absorbs are not killed in the process, but are instead stored within Muramasa's body. At any time, he can summon forth these Hollows to fight for him by exerting his red-black Reiatsu, which the Hollows emerge from.