Helgerån

Language: English (and some Swedish, but more than 90% English)
Subtitles: English for the Swedish-speaking parts

Synopsis:
The plot of Helgerån revolves around Sister Sarah, a devout Georgia native who’s living in a strict Christian sect and enjoying a romance with cop George. She hasn’t seen her twin sister, Gudrun, in quite a while since she’s, well, apparently possessed by the devil. Sara senses her sister needs her right away, so it’s off to Sweden where she becomes involving an ongoing saga involving copulation with the devil, meanwhile the church members are killed one by one

This is a kind of slasher, with some Nordic mythology thrown in. Quite gory at its moments, high body count. Quite atmospheric, shot in the mountainous region of Lapland