Ask that another way: Could TWG be just a benevolent Outsider?
Possibly. I'd considered that for a while after Cold Days came out. I mean, He's definitely an Outsider- He came from Outside, after all. He had to if He created the Inside. The question is are there different sorts of Outsiders? Different classes of being, with different motivations? In fact, I kind of wish I'd asked that in Virginia. S**t.
I'm imagining one of two major possibilities: one, that Outsiders are celestial entities on the same order as angels who opposed the idea of Creation from before the beginning. They didn't even have the fortune of becoming Fallen- they never got to the angel part at all, and became formless spirits of entropy and chaos. Two, they are remnants of past, failed Creations, and the Big Guy Upstairs decided (for whatever reason) that those old realities needed to go out of business. Now the laid off workers are camping outside the shiny new building built over their old lot, swarming the front door and trying to sabotage the scabs who work there now.