God - Devil

The people would believe anything a Pharoah said. That is just the way it went.

Your explination of turning water to blood is... almost feasable, but think of the plagues of frogs, gnats, flies, and locusts?? Could you rig that up... a couple thousand years ago? I wouldn't say so. And the hail, and the curse of the livestock dieing, and the 1st born children dying. I don't see any other explination other than divine intervention.

Frogs, locusts, and the others, who knows they could of gathered them. Set some kind of a trap for them then released a couple hundred. People were very ignorant back then and believed that one small thing was part of a larger thing.
Plague... Hmm... How sanitary were they back then??
Livestock dying... Shit just feed them poison or poison the food and it spreads to all of them. I doubt they had armed gaurd gaurding the food for the cows back then.
Divine intervention? You think that is more feasible than poison?