Justification: God is omnipotent, and hardly bound to this universe alone; He created all of them, unto infinity. Not that he wanted to--His power just unfolds that way. It is the most natural thing in the world, to create and create and create without limit. That's what makes humanity so special, of course. Bounded and individual--tiny flares of singular importance. Such finesse and such a microscopic scale takes great skill, and patience, and love. Humanity is is proudest creation.
Infinite universes are--well, it's finger painting. All bold strokes. Coloring outside the lines.
So anyway, of course God can hop universes. That's where he is now. The Darkness, too. Those with Grace, and a few other accoutrements. The children of humans and God's second-finest.
I'll see you again. Soon.