When Aoi was seven years old, he wandered into the Momochi House and was chosen as the Omamori-sama. He transforms into Nue to perform his duties, but it seems this role was meant for Himari.
When he transforms into Nue, he becomes an ayakashi the ears of a cat, the wings of a bird, and the tail of a fox. As the Omamori-sama, the nue protects Momochi House and eliminates demons who make their way in from the spiritual realm.
(Source: Viz Media)
