Draco in Leather Pants/Analysis

• There are many things to say about this trope:

1. All Girls Want Bad Boys (or boys want bad girls, girls want bad girls, boys want bad boys...)

Very simple. Villains often show the dominance, the rugged and wild physique, and the aloof Jerkass attitude that Heroes are much less likely to have. Fans who crush on these characters have a the power fantasy and wish to become the villain's main squeeze so they can feel protected and validated in their worth for having been able to inspire love in a monstrous person's heart. If a person like that can love them, it means they're special.

This used to be mainly attached to young female fans of male villains and the odd young male fan with a crush on the hot villainess, but with the rise in visibility among LGBT fans, for every girl who longs to be taken in by the hot bad guy there's a a boy who wants the same, or a girl who wants to marry the evil queen.

2. The existence of Love Martyrs in fiction.

Many a series with a male villain and his smitten female underling will have said underling experiencing an emotional roller coaster of whether or not he truly loves her or only sees her as a loyal minion to do his dirty work. She'll follow him anywhere, do whatever he says, fret if she fears she's angered him in some way and risk her life for him. She would die for him and sometimes she fulfills that promise. As for the male superior, he goes back and forth, one moment showing her affection and appreciating her hard work and the next being cold to her for her failures.

As for male love martyrs, this is typically shown through the man's admiration of a beautiful female villain's aggression. Many times, the lovestruck male character will tell the woman she's "beautiful when she's angry" and risk his life doing whatever she tells him to or even things she hasn't told him to do yet in hopes that his actions will earn him a crumb of praise from her. He'll take her abuse and belittlement simply because in his eyes, any attention from her is a good thing.

To some fans, to be able to stand by someone's side no matter what they put you through or how much of a monster they are is the ultimate expression of both undying love and unwavering strength, and therefore also a power fantasy. From this point of view, only a weakling would run away from mistreatment and only a disloyal traitor would abandon the one they serve in their time of need.

3. Reverberation of high status.

Villains are often ambitious. Since most of them often become kings, emperors, or have some form of authority, girls dream about being the respected dark queen at their side, whose high status ensures that no one will ever be disrespectful to her or disobey any order she may give as a the Dark Lord's lady. In other words, the freedom of being a bitch and not getting any flack for it. House proves that many men like being jerks and get away with it. Women are no different.

4. Evil Is Sexy.

It's true for men. Femme Fatales and Vamps are often considered "hot" by Fan Boys. While the heroine may look pretty, she doesn't ooze sexuality like villainesses tend to do, since, as we all know, a sexually active woman is not wife-material. Guys who dig evil women typically aren't looking for wives so much as they are the fantasy of being dominated by these beautiful but evil women.

Since this is inverted for males, the sexiness male villains ooze is often inherent and switches on many girls' desire to be dominated and literally owned by a bad man. Love Martyrdom often involves Sex Martyrdom and other kinds of unsavory things. All of this is nullified if the villain is physically unattractive or a downright rapist, though.

5. I Can Change Him.

The inverse of #2, in this case it's the feeling that the girl's (or guys as well) love is capable of changing the Draco. The Power of Love can do anything, right? This is more common in stories of male villains and female heroes, though there is the occasional fanboy who will have the villainess reform and become his devoted wife or battle partner.