Andrew Ryan
Let's talk about Andrew Ryan, the "king of Rapture." During his lifetime, this man was a legend. Without his hard work and dedication, we'd be nowhere. Born Andrei Rianofski, Ryan was born in Russia. Living in a communistic country taught him the values of a man's hard work and all that it can accomplish. After making his way to America to escape Russian's economic collapse, he soon found that not all corners of the world shared his views. With the dissipation of the myth that America was the land of opportunity, Ryan needed his own escape. Thus, Rapture was born.
Frank Fontaine
If Ryan was the king of Rapture, then Fontaine was the king of cons. Smuggling rings, contraband items, you name it. As an "entrepreneur," he employed the gorgeous Brigid Tenenbaum (we'll get to her in a bit) to create one of our most precious commodities, ADAM. In fact, he hired Tenenbaum and founded the Little Sister's Orphanage deep in the heart of Rapture, pretending it was because he's just that nice of a guy. In reality, he just wanted to get his grubby paws on the coveted element, making beaucoup bucks off the unsuspecting citizens of Rapture. In staunch opposition to Ryan, Fontaine made a respectable - well, you can't really call it that - living for himself.
Jack
This wily son of a gun is much more important of a man than you'd think. The illegitimate child of Andrew Ryan and voluptuous mistress Jasmine Jolene, Jack spent most of his adult life and his most infamous trip through Rapture under the control of another - Fontaine, masquerading as the everyman hero Atlas. Groomed to respond to commands prefaced by the innocent phrase "Would you kindly," Jack found himself to be the instrument of another man's desire to rise to power. On his journey through Rapture, Jack uncovered some very unfortunate truths about himself, as well as our underwater utopia. What's he up to now after destroying his father and making a break for it? Well, that's all up to you, if you know what I mean.
Little Sisters
And these charming little lassies? You don't want to have a run-in with them. These seemingly innocent little girls are genetically altered. Conditioned. Their purpose? One thing only - retrieve the precious ADAM from corpses. So if you happen to wander near a poor lost soul, I'd hasten my step. Where these little girls go, their guardians always follow. And you can't blame these mewling little children for being fussy. That hag Tenenbaum had a hand in mutating them, changing them with those disgusting sea slugs. You can find them hanging around Splicers (oh, you'll find out soon enough), extracting ADAM from the "angels." God help you if you bring one to harm, lest you deal with death incarnate.