Just don’t center it completely around them. I want other characters (especially the reader) to have their fair share of glory xD
THIS CONCEPT. HAS SHOT TO THE TOP OF MY "FAVORITE AUS" LIST.
It's really similar to an rp I've been doing with an irl friend with the whole death god/dess concept, so I had to include one of my OCs from that a little bit since idk how they'd go in normal sagau ehe
There was once a time when you physically ruled over Teyvat.
You had created everything- carved the seas from the earth, hung the stars in the sky, made the first plant grow, put breath in your people's lungs. It was those same people, though, that ended up pushing you to retreat to the underworld. They were independent, capable, self-sufficient enough. They'd proven to you they didn't need you. At least, not yet.
There wasn't very much in the universe outside of Teyvat. The void had been there longer than you had, endless inky-black sludge that consumed everything it touched. You had to carefully place a barrier around Teyvat to keep it from being contaminated.
You created a second plane parallel to Teyvat, carving the void away to make room for it. A place for the dead to finally rest. Between Teyvat and the afterlife, you carved a long, dark tunnel which you escorted the souls down with nothing but a lamp to light the way.
The whole process kept you alive. When you escorted someone over, they offered something up to you in return: their physical body in Teyvat. You fed off of their bodies and it kept you going, like a metaphysical symbiotic relationship.
You'd always assumed you were the oldest being to ever exist, and the only one to ever witness the void firsthand. That's why it shocked you so much when you found a small... creature licking the sludgy void off of itself, now trapped in your tunnel. You finished with the soul you were helping before you went back for it.
A small creature almost like a rat sprung from the void, fed off of it, and then chewed a hole in your carefully constructed tunnel. You destroyed the sludgy void covering the creature which was now spreading up the tunnel's walls, and the creature stared at you for a moment before shifting to a form mimicking your own. Copying you.
It followed you around as you went about your business, guiding the dead to their afterlife for several days before it began scratching the walls of your tunnel. Hungry.
And you realized you could solve each other's problems. See, regardless of the kind of person someone was, they'd be going to the same paradise when they died. You actually held lots of evil, undeserving people inside the plane of paradise. So you made a deal with it.
So long as it would punish the undeserving when they died, you would feed it. From then on, whenever a soul made their way down your tunnel with you, you would judge their life and the type of person they were, and if you deemed them unworthy of your perfect afterlife, you would feed their soul to your new... pet? Companion?
And that's how you met Mavros. Over time they slowly morphed their form into one of their own: purple hair pulled into a braid, bright red eyes, black horns and tail, gray cloak with a long black tail poking out. They also learned how to speak from mimicking you, starting off with a little squeak of "bye" as you walked away from a soul you'd just helped.
You regularly visited your acolytes in their dreams, communicating any guidance you choose to give them. Though you rarely do that anymore.
Unless you're in a situation like this.
See, the people of Teyvat had gotten it in their heads that you didn't want your creations to suffer through a death, and that included the animals. While this was true, you knew it was inevitable, and you could not survive without it.
You watched in shock as Jean explained the new rules to the people of Mondstadt. You yelled in frustration at your new friend, who copied your hand movements and mumbled similar words to yours. A toothy grin sat on their face as you look at them, unamused.
So you sent your acolytes a message like you used to, a not-so-cryptic dream involving you in a horribly malnourished state, the same priest walking away from you as you suffered. You doubt they knew what they were doing, but they needed to be told otherwise before they seriously harmed you.
The following day, the leaders of each nation met to discuss the dream they all shared. And when they realize what they were doing, they're mortified. They immediately set to punishing the priest who'd created the whole theory and offer up several offerings, plates on plates of perfectly cooked meats and other gifts for you being left at your shrines.
No harm no foul, you suppose...