The Vermillion are a breed of snakes, red and orange in color, that are first generation offspring of The Great Devourer and filled with its need to consume everything in their paths. Krux later obtained their eggs and began raising them in preparation for his eventual takeover of Ninjago. He then forced Ray and Maya to forge armor for them to inhabit as humanoid gatherings of snakes, threatening to harm their children Kai and Nya if they refused. He would eventually release the Vermillion after his brother Acronix returned to Ninjago, setting them to work kidnapping laborers-among them Cyrus Borg and Karlof-to work on material for their army and to complete the mighty Iron Doom.
The Vermillion were eventually manipulated by Acronix and Krux into inhabiting the Iron Doom, giving it the ability to fight, and used it to attack the Elemental Masters of the past. However, the Vermillion were eventually lost in time along with their masters and Sensei Wu after he removed one of the Time Blades from the vehicle.