Thermian (Astro City)

The Thermians are a alien race in Astro City.

Biology
As their name suggests they are humanoid beings made of fire.

History
The Thermians hail from a world in a different dimension. They have been at war with another race called the Frigians for years. Earth has been a battleground between these two races as it acts as an interface point between the Thermians' home-world and the Frigians'. Both groups keep opening spacial portals to launch attacks at one another from Earth, prompting the Honor Guard to intervene during these battles to minimize collateral damage.

Source

 * Kurt Busiek's Astro City Vol.2 #6 (1997)