The Nether is not uniformly heated, and has an atmosphere of dense gas that allows airborn organisms to thrive. Things get a little cooler and a lot more humid the further you go from the lava “oceans”. Despite how it seems, the Nether DOES have a lot of water — But it’s gaseous, not liquid. The nether is extremely humid, swamped in large amounts of water vapour that is typically too hot to condensate. The only areas it can condensate are in crimson and warped forests, where the fungi serve a similar function to baobab trees. Native nether organisms don’t have blood, they have a pneumatic system instead. Ghasts move through the air by inhaling and exhaling huge amounts of hot air, and have large sacks called ballonets that keep them buoyant. They feed on swarms of spores, static SE (soul energy) and microorganisms, and are highly territorial. They will brutally attack any other large organism in their territory, including their own young.
Minecraft OC art from a while ago. I gotta do more with this guy, I still haven't found a consistent way to draw him.
The lore behind him is that he's an ancient king of the Nether, and the blacksmith responsible for inventing Netherite alloy. He was born from the growingly dense population of belligerent souls in the soulsand valley as the war between Piglins and humans waged on, and was able to mediate the war for a short while.