[@RabidAnubis] Sorry this has been dead for so long, I've been having some internet issues at my end.

Yes this is based in 40K lore to some extent, the idea of the Raven Knights was inspired by the Dark Eldar Scourges. The mountain setting was inspired by a passage from A Thousand Sons. The irradiated and desert landscape was inspired by Fallout and an old tv show called Terra-Nova. Terra-Nova was also my inspiration for the hive domes alongside the hive cities of 40K. I imagine them as being a mix of Galifrey's dome cities crossed with an imperial hive city.