I know it's a far fetch before S4p1 was released but the OG Ninja becoming dragons (Cole eventually too) and the fact that none of the OG6 elements are part of the same Source Dragon I'm pretty certain that eventually the current Source Dragons die (probably by Ras master) and the OG6 (maybe except Lloyd so he still continues as master of the young ninja) become the new source dragons - permanently.... That folks is for a bittersweet ending, none of those beloved heroes would be able to...