Lava Men are a fictional terrestrial race featured in comic books published by Marvel Comics. They are frequently presented in an antagonistic capacity and have fought up against the likes of the Fantastic Four and the Avengers.
The Lava Men were descended from an extinct subterranean race known as the Gortokians. Aeons ago, the Gortokians encountered Cha'Sa'Dra - a being whom they believed to be a living god, but was actually a minor demon. In exchange for eternal servitude, Cha'Sa'Dra offered the Gortokians the gift of immortality, which they immediately accepted. Cha'Sa'Dra transformed their humanoid bodies into a race of bipedal humanoids composed of living lava. These Lava Men served their living god loyally for thousands of years.
During the "Inferno" event, Cha'Sa'Dra was one of the demons called upon by N'Astirh to attack the surface world. Cha'Sa'Dra was destroyed and with his death, all of his enchantments disappeared, including that which gave the Lava Men their immortality. Only those protected by the magic of the Lava Men's witch doctor, Jinku, survived. However, these survivors turned into beings of petrified stone, unable to move or speak. Jinku knew that the Avengers played a hand in the fall of Cha'Sa'Dra, so he summoned the Avatar of Cha'Sa'Dra to fight them. (Avengers 306)