Jane Foster
Although she's said she won't be involved in The Avengers movie...seriously, how can Whedon resist?
Played By: Natalie Portman.
Tigra
The Comic-Book Character: Unusually, Greer Grant Nelson was already a costumed crime-fighter, The Cat, before she became a superhero.
But she was transformed by the ancient race of Cat People into legendary half-human, half-feline Tigra, giving her fur, claws and great strength and agility.
The Movie Version: Here, Tigra is well known to the Avengers, but considered too loose a cannon to play as part of the team.
Nevertheless, they are forced to seek her help when a little feline intuition comes in handy in a raid on HYDRA's jungle lair.
Played By: Angelina Jolie
Hellcat
The Comic-Book Character: Patricia "Patsy" Walker was an ex-teen icon who dreamed of becoming a superhero.
Thanks to an old suit from Tigra's old days as The Cat, that's exactly what happened.
The Movie Version: Tigra's apprentice - human, but brought up in the ways of the Cat People and so virtually indistinguisable in manner if not look.
To make up for her lack of true felinity, she fights dirty. Hence the name.
Played By: A cast against type Amy Adams.
Madame Hydra
The Comic-Book Character: HYDRA high-flyer Valentina Allegra de Fontaine was also Nick Fury's ex. No superpowers, but trained to perfection in combat and espionage.
The Movie Version: HYDRA's head of operations: not unlike a comic-book equivalent to From Russia With Love's Rosa Klebb.
Played By: Michelle Rodriguez
Maria Hill
The Comic-Book Character: Nick Fury's Deputy Director at S.H.I.E.L.D, with particular links to Tony Stark.
The Movie Version: Easy to see her starting as a secretary figure who rises through the ranks to grow in importance...
...and since she eventually becomes an Avenger, she could be one to bloom in the sequel.
Played By: Carey Mulligan
Pepper Potts
The Comic-Book Character: Tony Stark's secretary and unrequited love interest, Virginia "Pepper" Potts.
The Movie Version: Familiar enough by now, since Gwyneth Paltrow has already played her in the two Iron Man films.
Character-wise, she's gone to become CEO of Stark Industries, potentially giving her a cameo role in The Avengers greenlighting Stark's latest crime-fighting gadgets.
Played By: Gwyneth, going for the hat-trick
Titania
The Comic-Book Character: Timid weakling Mary MacPherran willingly agreed to follow The Fantastic Four's arch-nemesis Doctor Doom in exchange for powers... so he made her a she-woman.
The Movie Version: HYDRA's muscle, and a girl who can teach the male-dominated Avengers a thing or two in a scrap.
Played By: Megan Fox
Katherine "Kate" Bishop
The Comic-Book Character: Bishop became a proficient combat expert after being attacked in Central Park; eventually she'd become Hawkeye for the Young Avengers.
The Movie Version: A local kid who Hawkeye (Jeremy Renner) saves from an attack and takes under his wing to train her to fight back.
Played By: Ellen Page
Sin
The Comic-Book Character: Daughter of Captain America's nemesis The Red Skull, Synthia was age-accelerated to fast-track her into his evil plans.
A self-styled evil Mother Superior, Synthia assembled criminal gang the "Sisters of Sin."
The Movie Version: Much as the above. Sin kidnaps orphan girls and brainwashes them into becoming formidable fighters.
Trouble is the Avengers are aware they're really innocent and won't hurt them...which gives them a significant advantage.
Played By: Mila Kunis
Firebird
The Comic-Book Character: Hit by a radioactive meteroite fragment, Bonita Juarez developed the power to generate heat and flames.
The Movie Version: Another ally of the Avengers considered too hot to handle full-time, Firebird is a freelancer called upon to help out with pyrotechnics when things start hotting up.
Played By: Penelope Cruz
