Full design of my Sona :3! I like suit ok shhh (also yes, they're now known as Rainy/Creator/Reyn, use whichever name you want!)
I've created quite the lore for them and I will ramble your ears off (this is a threat 🫵 /j)
TL;DR:
Reyn's a god of creation of sorts and watches the stories of the different created worlds unfold while never interfering with it, hence the title "Silent observer of the Unfolding".
Ashen is a manifestation of Reyn's insecurities and hatred for the created worlds and often seeks to destroy some of it, creating that whole symbolism of yin and yang, creation and destruction, life and death. They can't exist without the other.
The divinity/god like thing doesn't exist outside of the created worlds and they're simply a normal person with magical paintbrush.
I like to give my characters powers, why is that a thing? I've no idea but my Sona essentially has one as well. Now how strong their power is depends on which world/universe they're staying in because if it's one I created, they're essentially like a god of sorts and can change anything about that world whether for the better or worse. Though that's kinda where the title comes in: "Silent observer of the Unfolding" because they never actually set the course off the track and simply watch the story of that world unfold on its own.
They can interact with the characters,, because I say so and I'm a sucker for my characters nowadays. It's usually nothing too big though and most wouldn't even trust Reyn just from the vibe they give (no, they don't interfere with the characters thoughts and opinions, that's just tyranny ._.)
Now ya might notice the yin yang and my little stupid ass quote of "In every heartbeat of creation, there's a whisper of destruction. One pulls the thread tighter, the other loosens it.", what is that supposed to represent? I decided to create a 'counterpart' of Reyn whose placeholder name is currently Ashen that's basically the manifestation of their insecurities and hatred for the created worlds. So Ashen is basically Reyn, but they want the created world gone (Ashen doesn't exist outside of the created universe solely because there's no reason for them to manifest in another's story so they remain as emotions).
Reyn and Ashen do clash whenever Ashen manifests, because Reyn is like the sentinel of these worlds and keeps their existence alive while Ashen seeks to destroy it completely and utterly. Can they kill each other? No. Killing one another meant tipping off their balance as they can't exist without the other, hence the yin and yang and the mention of 'Creation' and 'Destruction'.
I did mention that their power depends on where they are: it's pretty simple actually, they're just some person with a paintbrush as a weapon (that paintbrush got power, yes). Nothing god-like 👍