Vanarus, Machaka Lion Kings etc

[Kobal2]

I'm not aware of any specific mythology or folklore associated with them, but Scandinavian vikings did historically displace to and eventually ruled a good chunk of western Russia way back when.

Considering the Kievan Rus military history and its on-again, off-again alliances with steppe nomads (Khirgiz, Kazhars, Cumans, Pechenegs...) I wouldn't be surprised if Vanarus had a horse archer component to supplement the Vans.

ETA : It'd also make sense in purely Dominions terms - Sauromatia's barbarian cavalry doesn't figure in Pythium's roster. My guess : they moved somewhere else (Vanarus) before winding up lording it over T'ien Ch'i