LOS ANGELES — Locked in a tower lingering above a fantastical floating city, past electrical barricades and steel doors, is a curious young brunette woman in a long blue dress that's just a few shades darker than her big, expressive eyes. Her name is Elizabeth, and with an enterprising blend of art and technology, the creators of "BioShock Infinite" have aspirations that she'll be the most human-like character to ever appear in a video game.
In the eagerly anticipated follow-up to 2007's "BioShock" – a hugely popular undersea first-person shoot-'em-up – players are cast as Booker DeWitt, a gruff ex-Pinkerton agent who rockets to the cloud city in 1912 to track down this mysterious woman. Within the first hour of the game, he frees her – but that's just the beginning of their journey together in the airy yet foreboding kingdom of Columbia.
"After Booker breaks her out, all she wants from life is to control her own destiny," said Ken Levine, creative director at "BioShock" developer Irrational Games. "It turns out she has these incredible powers to tap into other dimensions. One of the reasons she's locked in that tower is because she can bring things through from other dimensions. Obviously, that has a huge impact on the gameplay and the story."
As players battle foes across Columbia, Elizabeth can rip open space and time, offering Booker advantages like turrets that can blast baddies and scenery that provides cover from enemy fire. Sometimes it doesn't go according to plan. At one point, she seemingly thrusts herself into the 1980s.
Elizabeth is more than simply a time-bending helping hand though.
Levine is hoping Booker's companion provides a new depth to "Infinite," one that wasn't explored in the original "BioShock," whose voiceless protagonist didn't have a sidekick. It's been a daring and daunting endeavor for the game's makers, considering Elizabeth was originally envisioned as a completely mute, scripted character.
Over the past five years of development on "Infinite" at Boston-based Irrational Games, Elizabeth has evolved into the most complicated facet of the game. The designers opted against traditional storytelling techniques, such as cut scenes, instead aiming for a leading lady who could interact with the game's hero and virtual world without constraints.
Squad mates, superhero sidekicks, buddy cops and other types of companion characters are hardly new to the interactive medium, but Elizabeth is among a new crop of right-hand women in games, like the fragile young Clementine in "The Walking Dead: The Game" and the feisty gun-toting Ellie in the upcoming "The Last of Us."
They're young and female, yes, but they ain't exactly Princess Peach.
Levine acknowledged there are obvious parallels between Elizabeth and Rapunzel, but the veteran 46-year-old game designer was also motivated by his personal life when creating Elizabeth. He drew from his own experiences with an ex-girlfriend, whose previously abusive relationship inspired Elizabeth's struggle with Songbird, her monstrous winged jailor.
Courtnee Draper, the actress who voices Elizabeth, noted that Elizabeth helps Booker just as much as he assists her as they traipse across Columbia. She believes Elizabeth will rise above many two-dimensional characters in games, thanks to the potent combination of artificial intelligence and Elizabeth's story arc.
"When you first meet Elizabeth, she is very different than the Elizabeth that you grow to love and see at the end of the game," said Draper. "She has a huge range of emotions, which naturally make her more genuine and compelling. I think Ken's narrative underscores that. She's not some expositional character."
"Infinite" won't be released until March 26, but Elizabeth has already inspired "BioShock" fans to craft costume recreations and artwork. However, there wasn't always love for her at Irrational Games. Amanda Jeffrey, a level designer nicknamed "Liz's brain," said some of her colleagues wanted to cut her from the game because she kept "breaking" every 10 seconds.
"She'd look the wrong way, walk into a wall, be in the way or wouldn't throw you something," said Jeffrey. "We started progressively fixing more and more of those problems. She'd then break only once a minute, then once every five minutes. Eventually, we managed to get her working long enough that people stopped hating her and started loving her again."
Jeffrey and the other designers had to strike the right tone with Elizabeth. She couldn't be too creepy or too needy. Her virtual behavior is a finely tuned mix of scripted actions and random elements. She's been programmed to subtly understand where Booker must travel to next in Columbia without providing any "are we there yet?" antagonizing.
"It's really tough to make a companion character that doesn't annoy the player," said lead programmer John Abercrombie. "There was always a litmus test with Liz. We constantly kept asking ourselves, `Is this the right thing for Liz to be doing right now? Are we annoying the player?' We had a general rule that Liz could never nag the player."
Emotionally, one of the biggest challenges was determining the right level of eye contact Elizabeth should maintain with the player. She originally gazed at Booker for too long. Jeffrey and Abercrombie thought it came off as weird. Then, she hardly glanced at him. That also felt creepy. They eventually achieved a natural balance with Elizabeth's mint-blue eyes.
"I wanted her to be like a little sister," said Jeffrey. "In my mind, Liz was almost a real person, one that I cared for and was downright protective of within the studio to an almost naughty degree. I think having that kind of personal relationship with Elizabeth helped me ensure she didn't end up as a cutout character."
The expectations for ""Infinite," which was delayed several times since its original release date last year, are sky high. The original "BioShock" sold more than 4 million copies and was honored with scads of awards. Levine and the "Infinite" designers aren't worried. Booker and Elizabeth are ready to soar.
Follow AP Entertainment Writer Derrik J. Lang on Twitter at . http://www.twitter.com/derrikjlang