I know you said you didn't want to get into your OC versus PC rant on the tags on someone else's post, but I'm very curious about what it is, or if you've already ranted somewhere that I could read
Alright, so a billion years later,
"OC" is a term indigenous to fanfic communities, short for "Original Character." It exists in direct contrast to the presumed majority of characters in fanfic, who are of course not original, but instead imported from the canon itself. It indicates that the character in question is entirely this particular author's creation, derived from nothing but their own mind, and under their complete control.
An OC thus has both freedoms and restraints relative to other characters. If you want Steve Rogers to have a taco truck he visits and you need someone to run that taco truck, you can put Yesenia Perez behind the counter and that's your OC. She doesn't exist in canon, and you have to justify every interaction she has with Steve, but you also picked her name, how she looks, how old she is, whether she's sold tacos to Nat and Bruce too or wouldn't know them from Adam. If you want to tell the story of the first Avengers movie from her perspective you can have her there for the final fight or at home watching on TV. You can decide if she ran and hid from the Chitauri, if she hid in paralyzed fear unable to make a decision, if she rallied and threw bricks at the invaders, if she picked up one of Hawkeye's arrows and handed it back to him and their eyes met and he was blown away by her beauty. You can choose if she hates the taco truck and is stuck there because she can't make enough money to quit, or if it was her dream that she's been working toward all her life. If she's sixty and married or fourteen and working the family truck after school or thirty and divorced, if she's selling vegan tetelas or refuses to even sell bean tamales because she literally named the truck Carne de MĆ©xico and she's protecting her brand, goddamnit. She doesn't exist outside your head, and so nobody but you cares about her until you make her, and nothing in canon will ever accommodate her presence, and no one can tell you anything about her is wrong.
"PC" is a term indigenous to roleplaying games, short for "Player Character." It exists in contrast to NPCs, Non-Player Characters, indicating the difference between a character whose actions are controlled to some degree by the player and every other character in the world. It indicates that this is the protagonist, a vehicle through which the player experiences the story of the game, someone with whom they are explicitly expected to identify and over whom they may have some control.
A PC thus has incredibly strict limits in their characterization, because they are not only part of, but central to the story of the game. If you're writing about Commander Shepard, you didn't even pick her name. You can decide what she looks like, if she's a woman or a man, but you do not get to choose whether she's met Tali and Kaidan or whether Anderson likes her or not. If you want to tell the story of the first game from her perspective, you cannot choose to put her on Noveria during the prologue; she was at Eden Prime, she activated the beacon, she was assigned to the Normandy and then put in charge of it. She does not run from fights, she does not sit paralyzed in fear; she is someone who makes decisions and shoots guns. She has genetic modifications. She has one of three limited backstories, all of which indicate she chose the military as a career and is still actively choosing to be a part of it. She is 29 years old in 2183. She is a pillar of the entire canon narrative and if you do things with her that are outside the scope of the game, it immediately makes your story canon divergent.
(Obviously, Shep is an example of the higher end of restriction, but you fundamentally can't have a functioning game that doesn't demand something of the PC. Tav is always tadpoled, always a skilled combatant, always someone who makes decisions. The Courier is always an experienced survivor of the Wasteland and cannot choose to not care about the Platinum Chip. The Nerevarine is always a former prisoner and never joins Dagoth Ur. No hero is ever able to be a child unless they can only be a child because that's part of the plot. There is no RPG so open-ended that the protagonist can be a true blank slate.)
These are totally different concepts that impose totally different writing challenges; even from the audience perspective, the response you're asking for is different between Yesenia and Shep. It's like comparing freeform poetry to a sonnet; or, for a more topical comparison, it's like the difference between an original novel and fanfic itself. An OC is whatever the hell you want it to be. A PC is built in the gaps and freedoms of an existing canon structure, and relies on those common touchstones of canon that are known and shared across the audience. They are not the same! Words mean things! Stop calling fanfiction original fiction and sonnets freeform poetry!
