Shirogane, being the Death Iburanigami, is capable of summoning and naming the monsters known as Ayakashi and turn them into 'Nameless' vessels. In old times, masks where used instead of this new technique known as 'Name Summoning'....Name summoning consists on a ritual to give a name to a lost spirit, turning them into vessels. It works for both vessels and Ayakashi, but in order to name an Ayakashi, you must have great endurance, strength and skill, because you'll get blighted in the process, no matter what.
"Grasping thy true name I bind thee here. With borrowed name I dub thee my servant. The name answers the vessel to sound, I dub thee as my divine instrument."
After saying that phrase, the summoner must give two names to the spirit. The instrument name and the human name. Like for example, Suzuhá consists of the instrument name Jin and the human name Suzu. To change a vessel into a weapon, the instrument name must be called. In the case of the red fox-like Ayakashi that's next to Shirogane, the name of it is Miné. The instrument name is Ryô. Shirogane calls it Minéha. While the blue one above is named Kazu. The instrument name is Sho. Shirogane calls it Kazuha.
"The name Miné, the vessel Ryô. Come, Ryôkki!!!!"
