The method they are practicing is called Eneas Ulvar in the universal world language; it roughly translates to pillars of four-element.
It is a powerful method but a highly dangerous one; so dangerous that if I removed my strings from inside them, they would be immediately destroyed by their own element immediately. In every session, I would create a seal inside them that refrained them from practicing without me.
This method was created by a very powerful organization called Jarak Ulvar; it was the order of the cruel monks who practiced four elements. It was an extremly powerful organization, and it was its core method; the people would only become a full members after practicing all twelve levels of it.
This order would take babies with level 1 basic elemental constitutions and raise them in groups of four, each belonging to a different basic element.
