Vinland Saga 1 by Makoto Yukimura
At the turn of the 11th century, the North Sea is in the grip of the Viking terror. The clever Askeladd leads his small band of mercenaries into London, with the aid of the ruthless young Thorfinn, son of a warrior in the dreaded Jomsvikings. But this is an alliance of convenience: Thorfinn has sworn to kill Askeladd one day to avenge his father's death. When a race begins to capture the prince and secure the rights to the throne, personal grudges will clash with the fate of a kingdom, and blood will be spilled!