Chapter 13
If we assume that he did indeed erase part of Norunoa’s memory, this would mean that he is able to do this without a magic tool unlike the magic police, unless he has something like that and carries it around with him at all times which would seem odd. Since I can’t imagine that memory wipe magic is taught as a standard curriculum, being forbidden magic and all, this would imply to me that his past relationship with the “brim hats” which was hinted at in the past is really close, maybe he even was an (unwitting) disciple 