The Beast archetype is a character - usually a man, usually the love interest - who is antagonistic towards the protagonist and sometimes the world around them. They are controlling, mysterious, and the story goal frequently involves them changing their ways because of the protagonist. The application of the Beast archetype when executing the Darcy Factor can either be extremely effective...or horrific.
I want to emphasise that the actual character of Fitzwilliam Darcy does not fall under the Beast archetype. He is a character who doesn't always say the most appeasing things in social situations, he is unafraid to voice his opinions, and when his emotions get involved he can do so to the point of being blunt. He is drawn to the protagonist because she challenges him but while he enjoys debating her and he infuriates her, it isn't his intention to be malicious or make her feel bad about herself. Yes, he evolves because of the events of the story - as all good character should - but he does it on an equal level to the protagonist. A lot of him is revealed, not fixed or altered.
In contrast, the Beast archetype brings about the masochistic and sadistic roles between characters. Which can be very effective in provoking emotions in the reader, whether the "Beast" is in the role of love interest - themes of love, hate and thin lines - or takes up a different dynamic in the story. However, this can also get really tedious. If the author is blatant or forceful in their use of conflict, the reader can feel like they are watching a kicked puppy. It doesn't help if the "Beast" does a 180 on at an alarming rate and decides that they want to love and protect their puppy against the world. Baby steps, my hairy frienemy.
I have seen the Beast archetype in many works of fiction, and when it is well handled it succeeds in executing the Darcy Factor with correct applications of conflict, tension and intrigue. However, even the most sadistic and mysterious characters need to reel it in a little. Otherwise the jig gets tiring real quick.
How do you feel about the Beast archetype? Where have you seen it succeed and where has it failed?