WARNING: The following contains spoilers for Birds of Prey (and the Fantabulous Emancipation of One Harley Quinn), in theaters now.
Whenever characters make the leap from the comic page to the big screen, there's typically some amount of change. Sometimes, it's just smoothing out the wrinkles that have developed in their personality or history; other times, they only share a name with their original versions. The Cassandra Cain of Birds of Prey is a very different character than the one who appeared in the comics. Instead, she actually takes some surprising inspiration from other comic characters -- including one of the Robins.
WHO WAS CASSANDRA CAIN IN THE COMICS?
Cassandra Cain was created by Kelley Puckett and Damion Scott as a part of the massive "No Man's Land" story arc that was running through all the Batman Family titles in 1999. Cassandra is the daughter of David Cain and Lady Shiva, two of the most fearsome assassins in the DC Universe. Her father trained her to become an even deadlier killer then them, forgoing basic communication lessons like talking in lieu of teaching her how to decipher body language and react within seconds. But upon being forced to kill a man when she was just a child, she fled her father and ended up alone and traveling the world.
She eventually found herself in Gotham City and befriended Oracle. After proving her skills, as well as her desire to help the world instead of hurt it, Cassandra became the new Batgirl. She slowly developed into a vital member of the Bat-Family, even becoming Black Bat before the events of Flashpoint rewrote reality. Her origins were altered slightly in the New 52 era, but Cassandra retained many elements of her origins and early characteristics. She was also given the new codename: Orphan. She's since remained a steadfast ally to the heroes of Gotham, playing major roles in Detective Comics and Batman & the Outsiders.
WHO IS CASSANDRA CAIN IN BIRDS OF PREY?
The Cassandra Cain of Birds of Prey is a significantly different character. This Cassandra seems to be a genuine orphan, going from foster home to foster home across Gotham. Her current foster parents are never seen, but they can be heard arguing about taking her in during one sequence. Cassandra has become very street-smart as a result of her situation. She's especially mastered pickpocketing, which she showcases repeatedly by stealing goods and items from almost everyone she passes. She's even more than capable of slipping out of handcuffs, a move that Harley actually steals off of her and uses against Renee Montoya later in the film.
Harley Quinn and Cassandra Cain have never really had much of a relationship in the comics. But, the film version of the characters actually hit it off very well. After Cassandra steals a diamond from Victor Zsasz, she swallows it for safekeeping. Harley is eventually sent by Roman Sionis to recover the diamond, and she captures Cassandra. While the pair wait for Cassandra to pass the diamond, they actually end up bonding. Cassandra even starts to look up to Harley as something of an aspirational figure. Although Cassandra's confidence in her is shaken when Harley seems willing to turn her over to save her own skin, Harley saves her life and wins her respect back. The film ends with Harley fully taking Cassandra under her wing, teaching the young woman her specific sense of style and skills.
BEHIND BLUE EYES
The relationship between Cassandra and Harley is completely unique to the film, but it seems to have some direct inspiration from the original comics universe. Harley's mission to watch over a young girl had some inspiration from "Behind Blue Eyes," a story arc featured in Harley Quinn #33-37 by Andy Lieberman, Mike Huddleston, Troy Nixey and Alex Sinclair. The story featured Harley trying to keep an eye on a young girl named Amanda. Every criminal wants to get their hands on Amanda because of the codes imprinted onto her eyeballs that can give access to a vault holding a disc containing very valuable state secrets. The problem is that Amanda will permanently lose her eyesight within two hours if she doesn't receive the proper care after opening the vault. Over the course of the story, the two bond slightly -- although they never reach the point of comfort that Harley and Cassandra do. That might be partly why the story ends as it does, implying that Harley decided to take the money over helping Amanda and leaves her blind.
This version of Cassandra Cain also has more in common with another of the Batman sidekicks than her comics version; she actually shares a closer origin to Jason Todd, the second Robin. In the Post-Crisis continuity, Jason was introduced as a street-tough character who was found trying to steal the hubcaps off of the Batmobile. This street-smart approach to the character ended up also becoming the primary inspiration for Tim Drake in Batman: The Animated Series. But it also makes perfect sense that a more grimy and gritty character that was raised on the streets of Gotham would respond so well to the current incarnation of Harley Quinn. It makes this Cassandra a very different person from her original form, but it's an interesting amalgamation of characters that results in something new.
Directed by Cathy Yan from a script by Christina Hodson, Birds of Prey (and the Fantabulous Emancipation of One Harley Quinn) stars Margot Robbie, Jurnee Smollett-Bell, Mary Elizabeth Winstead, Rosie Perez, Ewan McGregor, Ella Jay Basco, Steven Williams, Derek Wilson, Dana Lee, Francois Chau, Charlene Amoia, Chris Messina and Matthew Willig. The film opens Feb. 7.