The Inhumanly Alien Side of Mars - Clark Ashton Smith, Warriors of the Red Planet, Hyperborea and The OSR Martian Campaign

 Ages ago I had a Warriors of the Red Planet/Hyperborea rpg campaign that took place after the apparent destruction of Old Earth. The Green Martians & the colored races of Mars with the Aihai being part of the ruling cycle of royals on Mars. Unlike their ancestors, the Yorhi, the Aihai are not proficient in the use of advanced machinery, although occasionally one can be found operating ancient technology beyond the capabilities of human science, such as disintegrator rays.


 Eons ago the whole of Mars erupted in a civil war with the coming of the Great Old One  Vulthoom and his followers. The  ruling Aihais who eradicated most of the cult. Vulthoom was defeated and it and its followers fled underground, where they slumbered in suspended animation for centuries. Another radical cult of Aihai worships the Dweller in the Gulf. 

Richard Coban artwork from the Vaults of Yoh Yombis by Clark Ashton Smith. 

  These races exist along side the Red & Green Martians having retreated after the marauding of the Green Martian tribes started thousands of years ago along the dead sea bottoms. The Aihai have little to do with the warlike imposters who came from beyond the stars. Human colonists came and established themselves on Mars but things have been quite dangerous as Old Earth has been destroyed. Here's where we mix in Warriors of the Red Planet. 

There is rocket service and trade between the eight planets colonies but it's a very delicate balance in terms of resources and the human states of Mars. Into this mix comes the low lander races of Red men tribes of Leigh Brackett. And then you've got the far higher caste of Red men from Edgar Rice Burroughs royals who never mix. Well this isn't true because of certain norms and byways that gets  used quite often in the ERB stories. Now add to this mix the fact that the Green Death has wiped out centuries ago the alien Hyperboreans. Mars and Hyperborea align when the Boreas forces allow which is less frequently then one might imagine. So while a party might crossover onto Mars on the starwinds. They may find themselves stranded on Mars. 
Humanity cleaves to a few minor citystates where there are pro human and Martian factions abound. There are however a few minor 'Thieves cities' where humans, aliens, and others mix.