Vermin is a Vermillion. In the show, many Vermillion look identical to him.
Vermin is hatched from eggs of The Great Devourer, like all the other vermillion warriors.
Vermin traveled aboard the Iron Doom back in time to fight the Elemental Alliance. During the fight, Krux and Acronix betrays Raggmunk, Blunck and Machia, destroying them and taking the former pairs control helmets. Theythen used them to destroy the entire vermillion army. The snakes that made the warriors then fused with iron doom, including Vermins.