I was referring to his true Deadlights form, which is just a form of energy in the Todash. Energy that can be wielded like magic by dudes like CK.
I've never seen anything saying he serves as some eternal force or has any eternal purpose. Neither does Maturin, who is not a creator. He's a Guardian. He spit out the main universe becsuse he was feeling sick, but he too is just another Todash monster.
I really dont feel like digging, but the concept of the World Turtle creating the universe simply because he was sick has a lot more implications than it sounds. Writing it off casually that the Turtle is not meant to be a representation of God & cold hard reality would be bad faith at best.
Ill leave you with The Turtle regards the Deadlights as his brother, assigning them as an entity & reinforcing the opposition to itself. Thats really all you should need to know. What King may or may not have done with the lore regarding the Crimson King & the Deadlights is not as simple as people make it sound either. For example, the Pennywise monster uses the Deadlights.... but the Deadlights are located elsewhere. Thats complicated.