Fan Casting Namor Sub-Mariner

Namor is a very arrogant son of a sailor and a princess from Atlantis. Today, as King of Atlantis, he seeks to protect all the seas, oceans and inhabitants. However, land dwellers are still polluting the oceans and threatening ocean dwellers. After a nuclear test that destroyed Atlantis, Namor ran out of patience and declared war on the mainland. Will the people of the country be exterminated, or will something cause Namor to change his mind about the war?