Water Demons are a type of demons that live in Egypt.
According to Bes, in ancient Egypt every shepherd knew how to get rid of water demons.
As Carter Kane and Bes search for Zia Rashid, Carter notices movement in the water, but Bes fails to see anything. After the magician and the god find Zia Rashid's Tomb, the three water demons attack and Bes orders Carter to get rid of them as every shepherd knew charms against them, but the inexperienced Carter lacks the knowledge. Bes manages to destroy one with his "BOO!", but the other two drag Carter and Bes down and attempt to drown them. Carter manages to figure out how to tap into Horus' powers and unleashes a massive telekinetic blast that vaporizes the demons and parts the river.