Shadows are one of the ancient, or original, energies. They have existed since the beginning of time and always will. Shadow Energy forms in the absence of Primordial Energy, and comes from the unknown abyss beyond the reach of all that is known. Shadows act drastically different from Primordial Energy. While Primordial Energy is unstable and mutates into alternative sub-energies like Electromagnetic, or Raw Energy in little time, Shadow Energy is stable. When left alone, Shadow Energy does not change, it only grows. Very few circumstances, in fact, have the ability to mutate Shadow Energy (of these few, only one is natural). Shadows have been a constant, unchanging component of every dimension. Those unaware of its existence as an energy believe it to be an unnecessary force of nature, a simple law of physics, or even the empty absence of light. They are right to believe it obeys the laws of physics, but they couldn’t be more wrong about it being anything insignificant. While common shadows could be described as empty, as anyone can walk through them, those shadows are mere fragments - more the tell tale signs of true shadows than anything else.
Where do true shadows come from?
The unknown is what lies beyond where Primordial Energy ceases to stem. The most vital truth of the unknown is that it is the counterpart to the Original Merge and the origin of shadows. The original Merge created all energy that is known: Primordial Energy, Creation Particles, Elemental Energy. All these energies surround matter brought together by the Original Merge and reveal what is known. Meanwhile, far away from what is understood, in the vast emptiness, lies the unknown abyss. The unknown stretches beyond space and time, further than already incomprehensible infinitely, and is thus older than both the Original Merge, and time itself. In the existence of the singular, finite piece of matter, the abyss was all that there was. The unknown flourished within dimensions of possibility much like the one piece of matter despite time not actually existing. When the Merge occurred and time began, not only did everything from the unknown join into the now one and only dimension, but all that existed was now able to change through time. The immediate result was an ambiance as the unknown resonated with all that it was. Echoing itself louder and louder, the ambiance evolved into an energy: Shadows. This is how it began that in the absence of Primordial Energy, in the alluring emptiness of the unknown, Shadows came to be. Holding true to the seemingly basic claim that "Thus it shall be: in the absence of Light, Shadows will thrive.
Thanks for reading! I hope you enjoyed. If you’re curious about this world, I’ve began making a Wikia for it. It’s still far from complete but I have many pages of material all on this world. Link is here: http://bionicle-shadows.wikia.com/wiki/Bionicle_Shadows_Wikia