Board Thread:Episode Discussion/@comment-27567063-20160513023811/@comment-4010415-20160513024749

I think the way the powers transfer has to do with how the wizard set it up or something. And hey, he transferred the powers to them while still alive and continued living enough for them to promise to visit him, so that's also different from how the powers are usually transferred. It was probably just his way of making sure the powers would continue to exist even after he's dead, so there would always be four young women somewhere in the world helping people.