As said, the Troll Bridge in Danmark is where you can get the Troll Club. I'd bring 2 or 3 shields for the fight if I was you though.As far as getting a Heavy Frankish Axe, just check the Weapons at every major city you stop in. In my current game, there was one in the shop at the beginning of my game in Dorestad (in Friese).If you were also wondering about Widowmaker, you can get it for 11k from any named Weaponsmith once you have over 600 renown.

• Viking Conquest Location

Viking Conquest Location

I know that there's for sure a named smith in the city in Norway and in Dublin, but you can just ask the Host in any Tavern for a list of all of them for 30 penings.