A free mod for Mount & Blade II: Bannerlord, by RaiderFromNorth.
This is a simple modification of the native troop tree, and the Sturgian troops feel very Slavic with only the high-tier archers and berserkers offering Viking-style combat. You can play as a Slavic boyar or a Norse jarl!
Is the mod balanced? Probably not. But hey, now the Sturgian faction is more flexible and you can roleplay as a Slavic boyar or a Norse jarl!
The most important thing in this mod is that the Sturgian troops are more flexible. You can now play as a high-tier archer, a berserker, or even as a Norse jarl.
This is a very simple and easy-to-use modification.
