User blog comment:IamJakuhoRaikoben/Chapter 346: The Law of Retrogression, Review./@comment-16344653-20130802171121

wow I just noticed that Retro Magic is the same as Human Subordination. The only difference being that Retro Magic also makes the target look like children and Human Subordination also allowing the user to summon humans. So, that means the weakness of Retro Magic are Celestial Spirits