『Aya』

A fugurama-yōbi(文車妖妃), a spirit messenger, working under Kaya's wing. Her original form is a magical envelope that can be used to summon her in her human form, which consists of her having long blue hair with matching eyes wearing a long light blue yukata. She makes her first appearance in chapter 21 of the manga when Himari was looking for a replacement weapon from Noihara's weapon vault, having lost Yasutsuna during her battle with Kuesu, and again in Kuesu's hotel room after the field set around the hotel was broken when the latter was pushed back towards the window by Yuto's Light Ferry powers, vomiting out numerous weapons for Himari to use. Aya can store multiple objects inside her stomach, a sort of hammerspace, and regurgitate them when necessary to the disgust of anyone who witnesses it. She also appears to have taken a liking to Yuto, having teased him in the pool chapter of Volume 0 and in Chapter 64 after Kuesu's supposed death.