Lucifer was growing weary of his brother, Beleth. He had sent him on a simple errand, but it would appear nothing was simple about it. He was able to spy on his brother by using the eye of the Oracle. He had given her what she desired most in exchange for her eye until his brother was back in the underworld. There was an order and structure to hell that most did not consider.
Everyone thought it was all debauchery and pain. It was so much more than that. Each demon that dwelled here was like a pillar holding up the Parthenon roof, If one pillar was to be removed or moved it would crumble. That was the same in hell. Demon kings were not allowed to be away from their thrones for a long time.