So, I got a "little theory". I'm not sure it will fit into the storyline, but yeah. When the Great Beings discovered that the EP leaking from the center of SM(and that SM will eventually "rip" apart), they created the MU and its main inhabitants, the Matoran, and its sub species, Toa and Turaga. The Matoran species have the power to form into Kaita, a combination of usually three beings. Something I've been thinking is that maybe the GBs made this function to inform the Matoran/Toa/Turaga/Mata Nui that that is the way to reform SM, that three will become one. Thoughts?