Name derived from: Suijin or Mizu no Kamisama, Mizugami. The water god in japan culture. It is found in lakes, ponds, springs and wells, including serpents (snakes and dragons), eels, fish, turtles, and the flesh-eating kappa. (Wikipedia) 

Level: Power exceeds the level of mega digimon. One of the three gods of creations

Information: Mizumon is said to be created by Paumamon's tears. When she needed someone most, he was created to help her in her time of dire need. He was the one to form the water in the digital world. The water that fills the oceans, lakes, and ponds. Mizumon was seen to be very fatherly. One to be very kind, and one to give anyone a good laugh. But he also had a fierce side that he could keep well hidden. He was seen to be a general amongst powerful digimon. Protecting the innocent digimon in the digital world. If a dark forces started to arise.

A digimon named Herculesmon once tied Mizumon to his ship. So he could get safe travels through the red sea. To travel to the island of the lost. A place where weapons of olden tales were hidden away. Mizumon was seen as a threat by Azamon, the god of darkness, forced Mizumon into the darkest reaches of the dark ocean, to be trapped there for all eternity. 

Type: Dragonic Man

Attribute: Free, Vaccine

Field: Deep savers, Nature spirit

Some sample images of my idea of what he would look like: