Isahaya

Isahaya (諫早) is a member of the Amakusa-Style Remix of Church and Itsuwa's grandfather.

Toaru Majutsu no Index
In the anime he can be spotted in fourth episode of season 2 fighting the Agnese Forces.

Acqua of the Back Arc
In volume 16 it is revealed that he is Itsuwa's grandfather and the likes the idea of pairing her with Kamijou Touma.

Abilities
His main weapon is a mace.