Astral is contacted by Kei Isurugi, a member of the school of Onmyōdō that Nekoyashiki once attended, to perform a ceremony at a mountain. Itsuki accompanies Nekoyashiki and Mikan, but they are attacked by Kei during the ceremony. Kei remarks that he lost his sister, Sakuya Isurugi during a similar ceremony three years prior because Nekoyashiki left the school at the time to take Mikan to Astral. Nekoyashiki challenges Kei to a personal duel, and Itsuki upholds this, stopping the arriving Honami and Adilisia from interfering. Despite Kei's use of kuda-gitsune, Nekoyashiki manages to defeat him, with Kei pleased that he was able to pose some level of challenge for Nekoyashiki, his idol at the school. As Kei lies in defeat, Nekoyashiki reminisces on his last experience with Sakuya as the group watches an aurora in the sky.
〈協会〉からの紹介できたという“石動圭”。彼はいつきに「星祭り」を行ってほしいと依頼をする。その話の最中に現れた猫屋敷は、圭を見るなり驚きを隠せないでいた。いつきは現場へと向かう途中、猫屋敷から圭は同じ流派の兄弟弟子だと知らされる。さらに猫屋敷は「独り言」と言い、ある話を語り始めた。
Astral es contactado por Kei Isurugi, un miembro de la escuela de Onmyōdō a la que Nekoyashiki asistió una vez, para realizar una ceremonia en una montaña. Itsuki acompaña a Nekoyashiki y Mikan, pero son atacados por Kei durante la ceremonia. Kei comenta que perdió a su hermana, Sakuya Isurugi, durante una ceremonia similar tres años antes porque Nekoyashiki dejó la escuela en ese momento para llevar a Mikan a Astral.
