Souko Morinaga
守永 蒼子
1 anime · 1 manga · 2 voice actors
Background
This bio may contain spoilers.
Souko Morinaga was the reason as to why the infinitely powerful, dangerous forbidden Book of Friends was created by its young adult creator of a topmost s exorcist. This is because her meetings with Reiko Natsume gave the latter the idea of challenging youkai to various games, duels and "fights" in exchange for their name as a way to kill time she never would have with fellow humans.
(Source: Natsume Yuujinchou Wiki)