God is an unseen protagonist in both Joseph: King of Dreams and The Prince of Egypt. He acts as the guide of Moses, the protagonist and unleashes the 10 plagues on Egypt when Ramses refuses to free the Israelites. After Ramses finally relents, God then protects the Israelites when Ramses leads an Egyptian army to slaughter the fleeing Israelites, bringing down the parted waves on Ramses' army and wiping it out.
Moses gets the people away from Egypt and goes to Mount Sinai where he receives the ten commandments
In his other appearences, God is an angel. But in this film, he is a light.
He is voiced by Val Kilmer who also voices Moses.