To reform you need 3 holy sites which are in sweeden/norge/danemark that you can possess easily if Saxony didn't lose to Charlemagne, germanic religion got 4 holy sites Then ask all small counties to vassalize, they are likely to accept Increase your realm and create asap your kingdom. Get the ambition to become king of sweeden. I will feodalize with himĪt the beginning, start a subjugation to the duke under you get as much counties you can personnally.
My son/heir ragnarr lodbrok died of rabies at 15 yo. I reformed norse religion with this character and almost got all scandinavia. I recently start a game playing Sigur the ring (duke of uppland).