The reals aren't algebraically under multiplication; a simple equation like x*x=1 can't be handled in real numbers. The complex numbers are algebraically closed. So I suspect that God created the complex numbers.
God certainly had a fondness for the real subset. Measurements are real scalars -- so much so that it really does look like God created the reals. That's what's important to us. But the fundamental laws seem to require the complex numbers (or their equivalent, like matrices), and closure under arithmetic operations really does feel like it should be a requirement for the reality of the universe.
replies(2):