You have your own life. You've got friends (whether they be your buddies at the bar or your True Companions), a job (be it accounting or kicking ass), and goals (be it retiring by 55 or defeating the evil overlord). Things are going well.
Then someone drops the bomb: You're not your own person. You've never been your own person. You've been groomed, tamed, and measured to be someone else's Plan B. Everything you think you've done in your own name has been providing them with power. You've been a puppet all this time, and you have danced a merry jig.
The Pawn is a character who finds out that their goals have been crafted from whole cloth — by the villain. Everything they've done for the greater good has been meant to suit the villain's good. They are the Unwitting Pawn writ large. A Heroic BSoD likely ensues, followed by The Pawn deciding to Screw Destiny. Similarly named to the Unwitting Pawn, but somewhat of a different trope. The Pawn is frequently set up by a Tomato in the Mirror scenario.
Note: As this is a trope that reveals the true motivations of several characters, here be spoilers. This is your last warning.
- Bleach: Aizen has a hefty Chessmaster complex and in chapter 396, announced that every one of Ichigo's battles has played right into his hand, and eventually admitted that he's been manipulating Ichigo's life since the day he was born. While it may seem Aizen was just screwing with him, the Everything but the Rain arc reveals that Ichigo (and Uryu, for that matter) wouldn't have been conceived if not for Aizen, because it was his actions that allowed for Isshin and Masaki to meet.
- In Tiger & Bunny, Barnaby discovers a rather unsettling truth about his parents' murderer; it just so happens to be the one person he always regarded as a trustworthy adviser, mentor and parental substitute since childhood, who also ended up being the employer he enthusiastically works himself to the bone for. Copious amounts of psychic brainwashing made it easy.
- In Toward the Terra, Keith Anyan is a rather extreme example: not only his entire life was engineered to serve someone's purpose, but even his own body and personality.
- The DC hero Aztek. When Aztek had his own solo book, he was a man who'd been trained from birth by "The Q Society" to fight the incarnation of the Aztec god Tezcatlipoca in the modern world. When that book was cancelled, Aztek got ported over to JLA... where Aztek found out that (as had been foreshadowed in the solo book) The Q Society had been funded entirely by Lex Luthor, so that he could get a hero in his pocket on the Justice League. (The whole Tezcatlipoca thing was true, mind you, and Lex didn't want the world to be ended any more than anyone else, but he intended to get his money's worth in the meantime.) Aztek quits the team thereafter, but returns and makes a Heroic Sacrifice to free Superman from mind control by a galaxy-destroying menace.
- The four in With Strings Attached. They think they've been brought to the planet C'hou and empowered in order to undertake a quest to remove a curse on the continent of Ketafa. They were actually brought over as subjects in an undergraduate alien psychology class, and they were kind of shoehorned into the empowerment/quest, which turned out to be fake anyway. They don't learn most of this.
- Fatale from Soon I Will Be Invincible. After being nearly killed in a truck collision, she's turned into a cyborg by a Super Soldier program that turns out to be a front. It's only after she joins the Champions, the world's greatest superteam, that Fatale realizes that the man behind the front was Doctor Impossible, whom they're currently chasing. Worst of all, she's a forgotten pawn; Doctor Impossible created her at some point as part of another of his plans, but abandoned her when someone ratted him out.
- Galacia was also this to Baron Ether, making this all the more sad as she used the bomb built within her to defeat the aliens on Titan.
- Conrad the Sailor, from the novel within a novel Eye of the Jack, within The Devil's Playground. He finds out not only was his master maniputlating him to kill his enemies, but the greek serial killer he was trying to catch was actually a "pulp hero" like Conrad used to believe he was, and his killings were all forged by the master. I guess you can't tell who's the killer based on what language the notes were written...
- In the Night Watch books, the Watch agents are well aware that their bosses have complex plans, though are still unaware of just how much, and to what end, they are being manipulated. The second book deconstructs this trope to an extent, as Edgar, and independently Anton and Igor, manage to work out some of what Gesar and Zabulon are plotting specifically by thinking about the situation in terms of a chess game. Rematerialisation is compared to castling, Anton figures he's a pawn, Igor is actually a rook who captured another piece but was then left vulnerable, and Svetlana is a pawn that managed to reach the end of the board and become a queen.
- Heroes: When Niki and D.L. search for Micah, who's been kidnapped by Linderman, they find files that indicate their whole relationship was manipulated by Linderman to produce a child who could help him with his goals.
- Season three also reveals that Nathan was given his power by his parents, but not in the DNA sort of way but by using him in a medical experiment.
- In Jekyll, Dr. Tom Jackman finds out that his entire life has been engineered by the research institute he works at in order to facilitate the release of Hyde, up to and including meeting his best friend- a pawn of the institute the entire time- and cloning the love interest of the original Dr. Jekyll and arranging for Jackman to marry her. The biggest kicker? The institute was run by the Hyde-persona of his MOTHER.
- In season 4 of Babylon 5, Garibaldi discovers too late that he has been brainwashed by Alfred Bester into betraying his friends and furthering Bester's own plans.
- In NCIS, this is part of Director Vance's backstory. When he was a new agent, he was set up to be killed as part of a gambit to re-start the cold war.
- The hero of Jade Empire. The Player Character is the Last of His Kind, trained in martial arts under the tutelage of Master Li, and when Master Li is kidnapped by the Emperor's forces and his dojo is destroyed, the PC swears to defeat the Emperor. And once he does, Master Li kills him; everything — from the genocide of his people to the destruction of the dojo — was engineered so that the PC would kill the Emperor and deliver the throne to Master Li. Don't worry; he gets better.
- Another Player Character example ensues in City of Villains. After being broken out of prison, your character is told by Arachnos that you could very well be the "Destined One." That destiny, however, serves as being a sacrifice to prolong the existence of Lord Recluse.
- Perhaps the biggest Player Character example, however, stems from BioShock. "Would you kindly...", indeed.
- Raiden from Metal Gear Solid 2. He's been trained by the Patriots to trip up Snake, and his girlfriend and boss are both false constructs meant to deceive him.
- Also, Liquid to Solidus to Ocelot.
- Droguza from Arc the Lad 4. He believed that he was the last of the Niente tribe, but we find out that he was really made in a lab by Emperor Darkham's researchers.
- The end of killer7, where Harman's younger self tells Garcian that he is actually Emir Parkreiner, and has been observed and controlled by the government all this time. At least, we think that's what happens.
- In Super Robot Wars Z, it is revealed that Edel Bernal and all her life desires, memories and personality traits were crafted by The Edel Bernal. And after revealing the truth, he unceremoniously killed her.
- Both protagonists to an extent in Knights of the Old Republic. Revan faced the traditional Tomato in the Mirror with some Amnesiac Dissonance, but The Jedi Exile is heavily implied to be aware of this on some level from the start and simply can't escape it.
- Baldur's Gate: In the first game, it turns out the Player Character is one of the children of the dead god Bhaal, who were all meant by him to raise his power again and effect his resurrection, dying in the process. Fortunately, Bhaal could not really control what his children would actually do after being born with his taint inside them, even if it did give them certain inclinations.
- In Resident Evil 5, Albert Wesker discovers that he was this to Ozwell Spencer. Everything that made Wesker, well Wesker, was indoctrinated in him since childhood by Spencer. All part of Ozwell's plan to become the god of a superior breed of humans. However, Spencer was a powerless old man when the truth was revealed, making it easy for Albert to kill him and make a play for godhood himself.
- In Heavy Rain, the Origami Killer (by having him be someone Ethan Mars was tasked with killing in order to save his son) used drug dealer Brad Silver as a pawn.
- In the Flash RPG DragonFable, the Doom Knight Sepulchure turns out to be little more than a puppet for a higher, more sinister power. The Mysterious Stranger who resided outside of Falconreach turned out to not only be Sepulchure's master, but he also orchestrated the events of Book One so he could personally return Lore to the primordial darkness from which it came.