Draco in Leather Pants
When a fandom takes a controversial or downright villainous character and downplays his flaws, often turning him into an object of desire in the process. This can cause conflicts if the writers are not willing to Retool the character to fit this demand.
In fanfiction, they are frequently the love object of the local Mary Sue, who uses the power of love to redeem the character. In extreme cases, the affection these characters receive from fans can lead them to forget that they're actually still supposed to be villains. Or, on the flip side, even the worst crossings of the Moral Event Horizon can be rationalized, while any insult from the hero towards the villain is cast as deplorably mean.
Common reasons for this include the character being wicked in a classy or cool way, or a deliberate contrast to a hero the fans find too squeaky-clean, stupid, or weak. A physically attractive character is much more likely to be subject to this trope than a physically ugly one; Beauty Equals Goodness, after all, and shallow as it may be, it seems that, for some fans, this is the case even when the character's beauty only extends to their appearance.
Jerkass Dissonance usually plays a part in this trope; it is much easier for people to forgive and overlook the negative qualities and stress the Freudian Excuses that form a vaguely sympathetic back-story for fictional characters than it is to do the same for people in real-life, because the actions of the fictional character have no real-world effect.
Expect, also, for fans to make excuses for the character not getting any comeuppance for their sins, and, for bonus points, gloat if one of their hated and/or villainized characters gets the short stick instead, especially if the latter is the victim of the former.
If the audience seems to have a fairly good reason for preferring the bad guy over the good guy, you may have Unintentionally Sympathetic. For the fan villainization of one or more of the original protagonists, see Ron the Death Eater. When the audience embraces or admires a villain more because of his or her chutzpah and/or Break the Haughty potential than out of actual admiration, then it's Love to Hate. When done to a historical character, it's Historical Hero Upgrade.
Some villain archetypes, such as the Smug Snake (because of their off-puttingly arrogant personality), female villains (for exactly the same actions), and the Complete Monster (because of the severity of their evil deeds) are rarely susceptible to this. But it can still happen.
Loveable Rogue and Byronic Hero, characters you're supposed to admire even if they do nothing remotely admirable, may be the inverse of this trope. Magnificent Bastard often applies to both tropes, but this is a lot less certain for Draco in Leather Pants - he may be a character only a mother can love. "I can fix him" is a commonly expressed sentiment among fans of Draco in Leather Pants. See also Faux Affably Evil, Affably Evil, Foe Yay, and No Yay. When this trope happens in the series itself, it's Screw the Rules, I'm Beautiful. See Rooting for the Empire for doing this and knowing it, and Jerk Sue for when the writer does this.
Character tropes related to/in danger of becoming Dracos in Leather Pants:
- Affably Evil
- Aloof Big Brother
- Bastard Boyfriend, Bastard Girlfriend, and Bespectacled Bastard Boyfriend by design, since these types are supposed to induce Perverse Sexual Lust.
- Bishounen or Bishoujo Villains
- Crazy Awesome or Creepy Awesome characters (if evil)
- Cry for the Devil or, rather, characters who invoke it, if the fans feel so sorry for them that they forget that they're still supposed to be evil.
- Dark and Troubled Past: because it totally justifies any of their negative attributes.
- Dark Messiah
- Evil Is Cool
- Evil Is Sexy
- Evil Virtues
- Hot Guys Are Bastards
- Jerkass Woobie, if the 'Woobie' part is used to automatically excuse the 'Jerkass' part no matter how out of proportion (or unrelated) the one is to the other.
- Knight Templar, if the fans agree with them.
- Laughably Evil, if funny enough
- Magnificent Bastard
- Offstage Villainy
- Progressively Prettier
- Self Fanservice often accompanies this trope.
- Too Funny to Be Evil
- Troubled but Cute or Broken Bird if they are evil.
- Used to Be a Sweet Kid
- Villainous Valour
- Well-Intentioned Extremist
- White-Haired Pretty Boy or White-Haired Pretty Girl
- Woobie, Destroyer of Worlds
- Comic Books
- Harry Potter
- Live Action TV
- Professional Wrestling
- Video Games
- Web Comics
- Web Original
- Western Animation