You may see the light as a physical element, but what you don't know is that its original form was humanoid. He was brilliant and bright as ever, but one day, he saw something profound...he saw a shadow...He didn't know how that was even possible, but there it was. Days went by and more shadows appeared until darkness enveloped half of the Earth. Light didn't know what to do, he didn't even know who or what was doing this...it was scary. Another day passed and suddenly Light felt something, he could only describe it as...cold, he felt cold. Then all of a sudden, another entity appeared, they looked a lot different from Light, but yet somewhat similar.
"Who are you?" He asked.
"I am Dark" She said.
The Dark was pitch black, and feminine. She must have been the one causing the shadows across the world. Light felt another new feeling, love. It may seem ridiculous to say it was love at first sight, but he couldn't think of anything else to describe this. She was about to flee, when he grabbed her wrist, it burned him but not by heat, by a chill.
"Goodbye, Light" She managed to say while escaping Light's grasp.
Before he could protest, she was gone, and he was lonesome once again.
Now Light and Dark chase over and around the earth, giving humanity day and night.
Dark and Light may never see each other properly again, but there is always hope.