It is interesting how nobody knows why the magic gems are needed; everyone is just following orders.
I wonder if a central idea of this series will be "being able to live normal lives." There are all of these mages ruining the lives of others in the human world, and now we get mages from Doroi who don't seem to be able to live normal lives either. Osoegawa is just pursuing a simple life, and getting others to experience that sort of happiness too.
Also, the yoga from chapter 11 strikes again. I must say that it is some pretty effective yoga!