I watched this film sometime in the past decade, in colour, in English, pretty likely made since the turn of the millennium although I didn’t see it in theatres. Opens with a battle scene, I think in North Africa, before the action shifts to England. Going by costumes (similar to Amish or Pilgrim garb) it’s supposed to be the 1600s or so. The population is being preyed on by a race of demons or undead, and the main character is limited from intervening by a vow of nonviolence. Might have been adapted from a comic book, and has an overall atmosphere similar to that of Death Trance (2005).