Most likely Pareidolia/Concerned, just like Kaori.
Pareidolia has been described as "The Dark" with a connection to Spiders, while Kaori has called herself "The Mistress of The Dark" and "Queen of Spiders":
And Pareidolia has been implied to be some kind of patchwork god through it's book's description, the way it's mall pulls things in, and it's ability to do what the other gods do:
While Nao-Chan seems to be some kind of amalgam being, adopted by Kaori.
There's also how Nao (The Xoanon) has implied some connection to Pareidolia/Concerned:
And there seems to be some implied connections to The Old One and Niki based off this in Pareidolia's reset:
Both of which, Nao-Chan has been involved with:
Overall: Nao-Chan and Pareidolia seem connected. Of course, there could be something else going on. This is ultimately just a theory.