Here you can learn more than you may have ever wanted to know about the cast of Faces.
The Left Face, named Left, is generally unwilling to go along with whatever's been cooked up on the latest attempt to succeed as a truly good webcomic. He's usually attempting to sabotage or snark his way out of the project. He may have some form of latent genius, though, depending on who you ask. You could call him id and he'd wonder what you were talking about.
The Right Face, born Right, is usually more level-headed than Left, occasionally can be convinced to join in the fun, but will often wreck adventurous attempts by getting far too interested in the metagame than the game itself. He's unabashedly bright, but his intellect can often be bent to furthering Left's sabotage or sarcasm.
The Female Face, Agent of The Censors joined the cast later, against her will, after being sent out under the disguise of the Society to Prevent Senseless Violence to Comic Strip Characters (S.P.S.V.C.S.C.). She's been looking for a way to escape ever since. In a way, she's the most sincere of the bunch, because she believes that playing along might actually get her out.
The Robot - by the name of Vector, which should be pretty obvious. For some reason or another, the Faces needed transport. And to pass as something resembling humans. Possibly for a court date where Vector, under the influence of the Artist proceeded to kick a representative of a media cabal into his hat. Origins are hazy. Might have just been caprice.
The Artist, and/or his Evil Twin, in his latest form. Aside from the usage of the Ominous Black Box, the creator of the strip sometimes takes on a character form. If he feels like it. Even when in form, however, he wields considerable power over the course of the comic. After all, creator, y'know. Occasionally has an evil-twin-like being appear and attempt to do evil to the cast. As versed as they are in the Artist's particular brand of evil, they usually shrug it off.
Those are the major cast members. Henchmen, stick figures, and media cabal representatives appear here and there, usually good for a gag or for exposition, and then vanish until needed again.
If you've had enough, head back to the main comic page.