Ervys was a Mer man, and was the secondary antagonist in The Deep, and the main antagonist in The Crossing of Ingo. He was killed by Conor Trewhella after Mortarow killed Conor's father whil he was fighting Ervy’s.
Ervy’s has an ambition to remove all human blood of Ingo. But he does not understand that if he spills Sapphire and Conor’s blood he will be spilling mer blood not only human.
Ervys was an adult Mer, and like all Mer he had a seal tail. His exact age is unknown but he is surely older than Conor. His skin had a bluish tinge from the fact that he was pure Mer without a drop of human blood in him. Ervys was tall and muscular as a result of being a warrior.