An interesting theory. If we viewed it like a spectrum, you could say our universe is red and this one is violet. Similar in nature, almost side-by-side, but on completely different wavelengths.

[It surprises him a little that he knows that Angels are capable of crossing universes... how much did that Fallen Angel tell him?] I'm not sure. It might be out of my own power to even contact one, but if anyone from our universe could cross over to this universe, it'd have to be an Angel.