This is a rehost of @togenyan's former Yo-kai Watch 3 save editor, which was removed from his Github on December 20, 2018. This is the most stable version of the save editor, compatible with the EU/AU release of YKW3. A great place to find some info on adding Yo-kai is the Yo-kai Watch Wiki on Wikia, where I update info as it becomes available.
You have Yokai Editor b2 for Yo-Kai Watch Busters 2 Magnum & Sword?