A realistic movie with a ruthless evil character where good doesn’t always triumph in the end

In real life, good doesn't always win. Especially in the olden times, when there were no cameras, no phones, and no means of recording events, one can only imagine how many horrible incidents must have occurred simply because there was no one to witness them, or because the perpetrator was stronger or more powerful.

I am looking for a movie featuring a truly evil, ruthless character with no remorse and no regard for societal norms—someone who does whatever they please without hesitation.

Let me give you an example to get a feel of what I am looking for -

If you have watched the series Game of Thrones, there is a scene where The Mountain kills Oberyn Martell by pressing his thumbs into his opponent's eyes while vividly describing how he raped Oberyn's sister and then killed her. One can imagine Oberyn helplessness in his final moments. He finally finds out for a fact that the mountain did indeed did that and there is nothing he can do about it now that he is about to die.