In The Beginning...

The Irish god Manannan (see image) is the Son of the Ysan god Lir Who is the Son of Chaos which preceded cosmos. The idea of something before everything is mythologically powerful if logically contradictory:

in Norse mythology, there was a Void but then there were forces and entities in the Void;

the Rig Veda asks whether there was water there;

Genesis says that there was water there;

Milton's Satan flew through Chaos which was the "dark materials" for new creations;

in Narnia, there is Deep Magic from the Dawn of Time and Deeper Magic from Before the Dawn of Time;

in Alan Moore's Swamp Thing, magicians conjur the Original Darkness that was before the Creation, hoping that it will destroy Heaven;

in Mike Carey's Lucifer, some demonic alliances go back to the Original Darkness;

in Starfarers, Poul Anderson summarizes scientific cosmogony that does seem to account for the emergence of being from nothing. See here and here.