"I suppose so? I don't really do that sci-fi stuff." Alternate universe, different realm, another world, they're the same, right? Hell if Strange knows any distinctions.

Starting around the first of the month though...that lines up with everything else he's learned about this etheric weirdness.

"I don't know where the magic is from of who marked our souls in the first place, just that they've done so. Likewise, I don't know why they've specifically marked our souls and given us these memories and odd dreams." Strange just knows that it's happened, not the why or the how. Nightshade wasn't entirely specific on that part.