That personal magic sure is some crazy convenience.
This has to be related to the "prophesied reincarnation" right? Is that common knowledge? If it is that's really painting a big target on their supposed miracle baby.
Multiple child kidnappings is low priority because no corpses, are you kidding me? People would be rioting in the streets if that kind of thing wasn't treated as a high priority case. These are not impoverished farmers in the boonies goddammit.
The kidnapper has a skill that makes threads move hundreds? of meters on command, ignoring the need for seeing the target and makes the threads completely immune to both physical and magical damage, what the hell!? Why don't you just say he's got god mode on.