From Creatures Wikia
The Flame Norns are a norn genetic breed by Grendel Man. They are lovers of heat, and need it to survive. Otherwise, their digestive system will shut down, leading to death by malnutrition. They make heat with every breath, however. Heat is also used to turn ADP into ATP. This helps them fight ATP Decoupler long enough to get to a yarn fruit. They have complete immunity to Heavy Metals, which allows them to live in radioactive enviroments. They are normally a peaceful breed, but they are good grendel hunters. They also like to use teleporters when crowded or scared. They use the Hardman Norn, Magma Norn, and Butterfly Norn Sprites.