Tsarist Russia is a Russian empire based out of Moscow. They are a much greater power now that Europe has been sieged by Svalbard, leaving them with minimal competition. They are expanding into the north and have kickstarted the Polar Wars with the Svalbardic Empire, fighting for the massive Svalbardic sphere of influence formed by alliances with China, the Ottomans and the Mughals, the greatest surviving world powers. Tsarist Russia now has control of most of the Russian Arctic and of all of OTL Russia, therefore making them the second greatest of the Arctic empires. This is a open timeline, so feel free to have the Russians go in any (plausible) direction you want, as long as I approve of it.