Yes, in the 3rd major arc Thorfinn finds out that Floki was the one who ordered Askeladd to kill Thors. This led to Thorfinn feeling very conflicted on his belief of no violence but he does clap Floki's cheeks w/o killing him and disbands the Jomsvikings.

What happens to floki Vinland Saga?

Additionally, Floki is also quite cunning, as he is the one tasked to convince Thors to return to combat and ultimately arranges for his death at the hands of Askeladd and his crew.

Does Thorfinn die in Vinland Saga?

Thors won the battle, but in exchange for Thorfinn's life, he was killed by many arrows from Askeladd's men.