I've got a few universes I'm working on.
The first one is mostly for my horror universe, where I have nine comics in a series.
Cosmic horrors and celestial beings do exist inside and outside of our universe. I mostly use subtly and implications for this because trying to creating the images of those beings can be daunting XD
I also decided to connect the supernatural with this cosmic horror. So you have demons, ghosts, warlocks, zombies -- they're kinda implied to be by-products of these beings, if not having an instinct that screams "these beings are dangerous" and are just planning for their arrival to come.
With that said, my universe is an earth where the supernatural is not entirely well-known UNTIL these dark cosmic beings start showing up. Then, people start to encounter the supernatural as itself prepares.
My second universe is more for my magical girl stories.
Science Fiction comes true with AI technology, intergalactic space, as well as the supernatural. These magical girl stories exist in the same universe but they're not connected in any way. Some happen before the others and are just stories within the universe. The ones that deal more heavily with the Sci-Fi approach are farther away in time (like 2100s and 2200s), while the ones that deal more with the demon aspects are in current times (early 1990s to late 2000s).