Isahaya

Isahaya is an old Amakusa-Style Remix of Church member who is over 50 years old. His main weapon is a maze of war.

In Volume 16 of the Light Novels, it is revealed that he is Itsuwa's grandfather. Apparently, he likes the idea of pairing Itsuwa with Kamijou Touma.

During the events of the volume 16 fought next to his comrades, Kanzaki Kaori and Kamijou Touma against Acqua of the Back. Later appears in the volume 17 next to other members of the Amakusa Church.

In the anime he can be spotted in chapter 4 of season 2 fighting the the Agnese Forces.