HIT GIRL
Kick-Ass
Chloe Moretz
In the argument of nature vs. nurture, Hit Girl clearly falls in the nurture category, given that she was raised by her father to be a pint-sized whirling dervish of devastation.

O-REN ISHII
Kill Bill, Part 1
Lucy Liu
Yes, we’re aware that, strictly speaking, Kill Bill isn’t sci-fi. But it surely is fantasy, of a sort, and the anime interlude which reveals this Yakuza boss’ origin is as pulp-tastic as it gets.

KATARA
Avatar: The Last Airbender
Voiced by Mae Whitman
Oh, sure, Katara the waterbender always felt merely like the stalwart best friend, the voice of reason. But when she’s pissed ... she can send a whole lot of H2O headed your way in a hurry.

HANNA HELLER
Hanna
Saiorse Ronan
On the other hand, Hanna was also raised by her father to kick unworldly amounts of ass, but she also has the benefit of—spoiler alert—a few genetic enhancements that make her stronger and faster than the average teen.

RIVER TAM
Firefly/Serenity
Summer Glau
Y’all know her deal by now: Driven crazy by scientists trying to turn her into the perfect killing machine. Rescued by her brother and stowed away on a ship-full of thieves, prostitutes, gunhands (and a preacher). A being of perfect, deadly grace.

CLAUDIA
Interview With the Vampire
Kirsten Dunst
Like so many of these young women, the decision to become a deadly little girl wasn’t hers: In Claudia’s case, a pair of dashing vampires (Brad Pitt and Tom Cruise) who wanted the perfect undead family.

ABBY
Let Me In
Chloe Moretz
And sometimes, little girl vampires are just lonely and will kill whoever they need to for some company.

SAMARA
The Ring
Daveigh Chase
I still have nightmares about watching this movie, let alone the movie itself, so I’m just gonna leave this here and not think about her one second longer than necessary.

ARYA STARK
Game of Thrones
Maisie Williams
It’s clear, even from what we’ve seen on HBO’s show, that young Arya Stark will grow up to be a force to be reckoned with—given that she’s already a sword-wielding spitfire as it is.

HERMIONE GRANGER
Harry Potter
Emma Watson
Safety tip: Never piss off the smartest kid in the class, especially if she’s got a mean wand hand.

CARRIE WHITE
Carrie
Sissy Spacek
Also: Try not to bully the class telepath. That sort of thing rarely ends well.

BUFFY SUMMERS
Buffy the Vampire Slayer
Sarah Michelle Gellar
Even though she’d rather be shopping and gossiping about boys, the Defender of Sunnydale will attend to her destined task: dispensing maximum slayage with style and wit.

ROGUE
X-Men
Anna Paquin
She can kill you with a touch; suck you dry and leave you a hollow, empty husk. And she’s one of the good guys.

BOLTIE
Super
Ellen Page
Even though, technically, Libby isn’t a kid, she fashions herself as The Crimson Bolt’s kid sidekick, so she gets a pass. And she will absolutely wreck you if she gets the chance. Seriously. With a Buick.

CHARLIE MCGEE
Firestarter
Drew Barrymore
Stephen King has a thing for super-powered kids and when you add the emotional immaturity of a pre-teen girl and the nigh-limitless power of a pyrokine, you get one of his most explosive protagonists.

KATNISS EVERDEEN
The Hunger Games
Jennifer Lawrence
Sharp eyes, full quiver, can’t lose.