Floki is a Jomsviking commander and was one of the principal Viking commanders under Sweyn during the invasion of England and subsequently under Canute. Floki is a central antagonist in Vinland Saga and the man who contracted Askeladd to assassinate his former comrade, Thors. This act orchestrated most of the events that happened in the series and caused great tragedy to the protagonist, Thorfinn.
Floki has fair hair which unlike that of other Vikings is kept trimmed to medium length. His beard is also trimmed to form a rectangle, giving his face a square-like appearance, and he doesn't have eyebrows. He has a large scar running down the right side of his face reaching down to his lip. He dresses in the same attire as his Jomsviking crew, although after his initial appearance when he was wearing a helmet, it has since been depicted without it.
Floki's only redeeming quality is that he genuinely cares for his grandson Baldur.
He is an extremely ambitious, cold and calculating man who'd stop at nothing to make Baldur chieftain of the Jomsvikings, even though Baldur had absolutely no interest in the chieftaincy.
Floki can also be very spiteful and petty. He held a grudge against Thors for many years, and eventually had Thors assassinated because of it.
Floki was only shown briefly in combat when he crossed swords with Askeladd after the latter's assassination of King Sweyn. However as only exceptional members of the Jomsvikings are made commanders, his combat abilities are presumably formidable.
He has been employed by Sigvaldi and Sweyn as an emissary with delicate tasks such as convincing Thors to return to the fold and attempting to convince Thorkell to renounce his allegiance to the English, indicating that he has a degree of diplomatic skill.
Floki served alongside Thorkell and Thors when the latter was still a Jomsviking and as a fellow commander is well known by them.
He had a deep-seated resentment towards Thors as he felt that Thors always looked down on him.