Powers: Flame projection. Flight. Can control their own mass.
Weaknesses: Extreme (arctic) cold.
Bio: This comics-only race lived in the magma veins running deep beneath the Earth. They could occasionally travel far away from this home, provided they could find a way to remain hot enough to do so.
They were basically peace-loving and helpful beings until Professor Vinter managed to convinced a few of their kind how to use their abilities offensively.
Like the SIlurians and Sea Devils, they are probably not an alien race, but a race so old and hidden that humans have rarely encountered them. Unlike the Silurians and Sea Devils, though, they are generally happy to coexist with the Earth's surface-dwellers.