Vinland Saga is my fav anime, though I haven't read the manga I've heard it follows very closely.
The first season only covers the prologue!!! The manga has to be deep for the first 24 eps to only set the stage.
So far, the anime has been about vikings(this much wont change) - different factions of warring nations and each party has a different goal. There are kings, and mercenaries, princes being targeted for execution, bodyguard roles, training scenes as the young MC grows into a fierce warrior. Family loss, and a lot of real world sadness. But this show is also at the top for me, one who doesn't like to watch dramas.
It's action scenes are amazingly done, the wit of the creator is shown in many ways in this series. Its intriguing and keeps you on the edge of your seat. I'd tell anyone to give it a shot. But hopefully you like action and aren't afraid of a little blood.