The term Cosmocrator is a Zoroastrian term. In the original Persian faith, God was believed to be everywhere, ruling everything. The very core of the monotheistic religions share this one central outset. When Akhentaten lived, Egypt was at its height. It was uncontested among nations of its time. It was a time where mankind took amazing steps forward into the known and unknown world.
Akhentaten was more of a philosopher than a pharaoh. He built his own city in the vicinity of what we today call Armana. He more or less built walls around himself. Making a little replica of what he understood as the spiritual world in total harmony on earth. He tried to build a kind of paradise. This paradise was really a reflection of the sun. He saw the sun as the only God. There was nothing besides the sun, nothing above, and nothing below. There was only the sun. This idea is what created monotheism. There is only one god, and that is the sun. On top of this, he saw a connection between the sun and man.
This gave mankind both a blessing and a curse. Because according to Akhentaten the sun blesses the earth through its rays, but it takes something back again. It gives us light, but takes our insolence and prejudice away. This we do not like as mankind. We do not like to be poked at when it comes to fallacies. He saw himself as the enigma of this idea, because he knew, as Plato knew, that he was entitled to bring light, but punished with hatred, prejudice and shadows, it should be a guardian of the light, or rather a bringer of light, a bringer of truth.