Finger-Lickin' Evil

Evil girls (generally cat girls or dark magical girls) are frequently armed with razor-sharp fingernails or claws as their primary melee weapon. If such is the case, her trademark gesture is to lick her claws in a cat-like fashion with a sinister grin on her face, sometimes while blood drips from them.

They generally stop doing this after a Heel Face Turn, because Good Is Boring.

See Also: Licking the Blade, You Taste Delicious, Evil Is Cool, Femme Fatalons and Creepy Long Fingers.

Anime and Manga

 * Arachne from Angel Sanctuary
 * Nao from Mai-HiME. (Whether she's evil is up for debate, but she certainly plays the part.)
 * Nariya and Eriya from Vision of Escaflowne
 * Delphine from Last Exile
 * Ophelia from Claymore
 * Masato of Mermaid Saga is one of the few male examples of this trope. While he doesn't have sharp finger-based implements of doom, he does make a point of licking the blood off his fingers after gouging Yuta's eye out to show how damn evil he is.
 * Variation: Ren licks his chops in Shaman King while his face has blood on it.
 * Another Variation: Road Kamelot from D Gray-man licks the blood off of the sharpened candle she pierced Allen with.
 * Due in Magical Girl Lyrical Nanoha StrikerS. Pretty nasty, too--you really should clean those claws, first...
 * Masane from the anime version of Witchblade is an example of a protagonist who licks her claws.
 * Another male example would be the title character of Inuyasha, who uses his claws as his main form of attack until acquiring his BFS.
 * His elder half brother Sesshomaru has been known to do this from time to time, although this lessens as he shifts from "a borderline Complete Monster" through Anti Villain to a type IV Anti Hero.
 * Rob Lucci, another male example, licks the blood off his thumb once during his fight with Luffy in One Piece. It's unclear whether the blood is his or Luffy's. (He does have cat claws, but they weren't at the time.)
 * In the OVA of Jojo's Bizarre Adventure, Dio rips through a group of civilians with a single slash of his hand, then laughs to Jotaro as he licks the blood from it.
 * Licking his fingers is also one of the multiple unpleasant habits of the villain Magenta Magenta from the seventh series of the manga.
 * Vega from Street Fighter II: The Animated Movie licked the blood off his claws after successfully attacking Chun-Li.
 * Psycho for Hire Wei in Darker Than Black is seen licking (his own) blood off his hand after killing a room full of people.
 * In a battle between Ranma and Ryoga from Ranma One Half manga, Ryoga manages to cause a small cut on Ranma's face. Ranma proceeds to wipe the blood off with his hand and lick it while saying something to the effect of looks like I'm going to have to get serious.
 * Dead master from Black Rock Shooter
 * Siam from Free Collars Kingdom often does this, to her own dismay.
 * The Trinity Blood manga has a relatively rare heroic male example: Here, we have Abel Nightroad helpfully reminding us just how scary the world would be given the existence of vampires that feed on vampires.

Comic Books

 * Sarah from the Witchblade comics sometimes does this.
 * Catwoman, one of Batman's Rogues Gallery.
 * Lady Deathstrike has extendible adamantium fingernails (originally she was just an insane swordswoman from Daredevil, now better known as a foe of the X Men, and Wolverine in particular) and occasionally licks them.

Fan Fiction

 * In the Mai Hi ME fan fic The Sword of the Lord, Nao, who has since become a The Atoner Anti Hero, resists the temptation to lick her Element, because "That's supervillian behavior and it gets your ass kicked".

Film

 * Rare Male Example: Geoffrey Rush's character in Mystery Men uses his over-long pinky fingernail as a knife, cutting up Ben Stiller with it.
 * Another male example: Kevin, from Sin City.

Western Animation

 * Yet another male example: Vega from Street Fighter occasionally does this in the animated series.

Literature

 * In Wizard's First Rule, Big Bad Darken Rahl has a few tics, among them licking his fingertips and running them over his lips and eyebrows, stemming from his being burned by Wizard's Fire when he was a boy.

Video Games

 * In both the Metal Gear Solid game and comic, Sniper Wolf gashes Snake's face with her nails to symbolise that he's her "special prey". In the comic, she licks her fingers. It looks cool as hell until the plot explains to you that the reason the Quirky Miniboss Squad is so worried about Snake is that he's carrying a deadly virus in his bloodstream. Though  it makes sense.
 * Male example: Kartikeya from Wild Arms 5.
 * Like the Western Animation example suggests, Vega does this in one of his poses of SF: Alpha. Though it's more Licking the Blade.

Professional Wrestling

 * WWE wrestler Mickie James lacks the razor-sharp claws, but still managed to pull off this trope off by busting Trish Stratus' forehead open, then wiping her hand against it and licking the blood off her fingers.
 * Not to mention her... slightly more risque use of this trope that actually got edited off of the DVD this match was released on.