Brutal (2017)

If you liked "Hostel" and are into torture horror, then this is a must-see see. The title is by no means an exaggeration, in any shape of the word, it's freaking BRUTAL
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Chapter 1, the actor portraying our protagonist, is freaking awesome, the far away look in his eyes and vacancy of humanity are brilliant.
Chapter 2, we find ourselves with a new protagonist, and "she" (our actress) has just as much ferociousness towards her victims, but hers come to her. Much more complexity to her character, but efficiently brutal nonetheless.
Chapter 3, our 2 protagonists, meet. The outcome of this meeting of the two can only lead to disaster, either for them or for the rest of the population at large.