The Powers did appear to transcend all worlds, but they'd never interfered directly, certainly not to this level. Which only left one other possible entity.

"There is one thing," Angel said slowly, "that would fit that description. They call it the First Evil. It's...supposedly older than time, older than the world itself. And I know for a fact it can open dimensional gateways to bring back—” He paused, frowning a little. "Bring back those who shouldn't be back. I can't—I don't know what its true motives are exactly except that it's pure evil, but judging from what it attempted the last time it was around, I think it tries to tilt the cosmic balance. Plucking warriors from the battlefield or converting them to its side."

The absurdity of certain aspects of this place didn't entirely point to the First, but the First also seemed to work through other beings, manipulating them. The doctor everyone spoke of could very will just be serving the First, possibly even without really knowing it.