Hino Jinsaku

He is a minor character appearing in the 4th volume. He's a serial killer, and suspected caster of Angel Fall. Touma and Tsuchimikado seek him out, and discover that he is in the house Touma's parents bought. Strange enough, he was not affected by Angel Fall due to the coincidence of having a split personality; he simply switched appearances with his split personality, and since the appearance is the same there it was no visible effect and thus he was suspected of being the one behind the spell.

In the epilogue of the 4th novel it was revealed that his execution is planned to be soon.

He only appeared in the novel, and was completely absent in the anime.

(Source: Toaru Majutsu no Index Wiki)
(Updated by Aezile of Toaru Majutsu no Index club)