Kek (Kuk, Keku) means darkness. He was the god of the darkness of chaos, the darkness before time began. He was the god of obscurity, hidden in the darkness. The Egyptians saw the night time, the time without the light of the sun, as a reflection of this chaotic darkness.
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"As a god of the night, Kek was also related to the day - he was called the "bringer-in of the light". This seems to mean that he was responsible for the time of night that came just before sunrise. The god of the hours before day dawned over the land of Egypt. This was the twilight which gave birth to the sun."