User blog comment:B214/Volume 21 info & spoilers/@comment-27876048-20160603161434/@comment-223.255.230.24-20160614181234

Erasing memory is one thing but erasing trauma is another as stated in Vol 14 about erasing memory spell. Although you may argue that the whole myth working together could solve the problem, but after losing a lot of their resources fighting 666 i honestly doubt they could erase the human race's memory about 666 incident.