ok this symbol represents the three energies
Black (Demons) and White(Angels) are pretty obvious right? anyway, the third one (the gray one dur :P )
this one represents all mortal life on Earth be it human or Anthro.

moving on, this symbol tells that these three are dependent on each other, they can't exist with out the other two. now normally they remain disconnected. seperate from each other but always coexisting. however Twilight Chimera are connected to all three at once hence why they are so powerful

anyways if i say more here it'll spoil the story soo comments on what you think please