The man who wanted to chase light finally did, but he didn't catch it. Or at least, not well enough to satisfy him. So the chase began anew, and light became dark, and dark entered the man's soul. This made him heavy, which slowed him down so each succeeding attempt to track and pin down light became more arduous and less fruitful. The chase made him crazy for all he could think about was capturing light, but light mocked him and flickered away at the moment of capture.
In the balance between light and dark, he went one way only to end up on the other side. In the end, dark permeated the man who would chase light. He stumbled one day and gave in to darkness; there he found relief from the hunt. The dark claimed him, as it will claim us all one day, and in being claimed, the man returned to dark, which is all light captured.