Emergent Character

Who Am I Playing?
Role-playing games are about playing a character or fictional person in a fictional milieu (usually) using some dice and some rules to develop a story with friends while often sitting around a table, but more recently often while online at the computer. Many games devote several pages of rules to generating this game character in some detail. Often the player is encouraged to begin character creation by imagining the kind of person they would like to play in the game. Many character sheets (record of character abilities, etc.) have spaces to describe the physical looks of the character such as eye color, height and weight, etc. Some have a blank box or space and encourage you to draw a sketch or doodle of the character to show others what they look like. Some even have a space for background material to be recorded.
A central theme of most role-playing games (RPGs) is that the player not play themselves, but rather attempt to take on the role of an imaginary person in a different world with motives, skills, and personality distinct from the person who is playing the character. Sometimes this character is drawn directly from a literary source or perhaps you are asked to play a person from history. In those cases the player has some resources in the form of what is already known about the character which can be used to inspire their game play. Generally the character will be entirely made-up just for the particular game, however.
So who is this character I am to play during the current game? Most games have guidelines to help define what sort of characters the game is about - in other words, who the cast of characters may include. Most old school games (the ones seem to I like best) suggest that the player should work with the game's referee (person setting the stage and facilitating play) to develop a character for play. That way the character fits well with the intended milieu and the referee can assist with any questions the player may have.
Alright, I have done that and now have before me a filled out character sheet, which is really just a piece of paper with some values written on it. Who is this? I could argue that the character is fleshed out, develops and becomes whole, only during play. Some players like to imagine elaborate backstories for characters, which is fine if they are consistent with the milieu the referee is working to develop, but people change and so do game characters. How the character grows and evolves over the course of play is one of the more interesting aspects of long-term play and often is a central theme in the story which emerges from play.
Play to see what happens is one approach to the RPG hobby and one which I am particularly fond of. Rather than script out a story and hope or nudge the players to follow the script (sometimes derisively called railroading), I prefer the freedom of a sandbox where players go where they want and we all find out what the story is together as it is happening. The same approach works for characters - play them to find out who they are. It's a more intuitive approach to the game, but can be a fresh alternative to planning and designing. (Using intuition one "feels" their way through rather than thinks their way ahead.)
Therefore with character sheet in hand I set out to discover who this fictional person is. Dice will play a part - it's a game after all, as will the in-game decisions I make (some thought through, some following intuition because "it just feels right") during play. If the PC lives long enough, we the players will find out what makes this PC unique. We may even come to like the character and care what befalls them. Whatever happens, it will be entertaining to play and find out together.