Hmmm.
I'm actually building up a nice mythos for the Cosmos in general.
All of Creation is made by the Omni. The Worlds themselves, and the inky Void that they swim in. The Void is part of creation, a dark and empty part. But things live there. Vast and dark and hungry. The Dragon was one of their number..
Outside of Creation, nothing existed. However, the power and energy and realness of the Universe spilled out into the Nothing.. It made a chaotic place of energy. The laws that governed our World held tenuous sway over this place, weakening as it grew larger.. Things live there. Wild and Anarchic.
The Gods themselves have a place. Timeless and powerful, it is a place where the weary rest for a time, whether that be for centuries or forever..
“She'd become a governess. It was one of the few jobs a known lady could do. And she'd taken to it well. She'd sworn that if she did indeed ever find herself dancing on rooftops with chimney sweeps she'd beat herself to death with her own umbrella.”
― Hogfather