Was the Exodus natural or supernatural, fact or fiction?

[John V]

To what end?

As already noted, to display more works. We're still talking about it thousands of years later.

Just so that he could kill the innocent first born instead of their guilty parents?

That and the other plagues that came after it says that god hardened pharaoh's heart.

Is that moral and good or is it God doing evil?

You'll say it's evil, I'll say it's just.