I just wanted to share some of the visual inspiration behind my Northern Nomad raiders. The initial idea and basic description of nomadic mammoth herders in chain mail and fur came from the World of Mortal Engines series of books, and my mental image was always of Cossacky-Vikings (or maybe even Vikingy-Cossacks, it's hard to tell!) - all baggy trousers, tunics, beards and long hair. Luckily that description pretty much perfectly fits 'Rus'/Eastern vikings, so they sort of became my baseline. I was also partially influenced by memories of National Geographic style anthropological photos of nomadic reindeer herders (Both Sami and their asiatic cousins).
I was also always really impressed with Dalaupporor's 'Baltic heathen' army ( Check it out here) and at the back of my mind I'd always fancied doing something similar, so that sort of fitted in too