When in a battle to the death, the winner has ultimate authority over the loser's fate. Maybe they could kill them then and there. Sometimes this means that the loser owes them their life, creating a life debt that could only be repaid in the most extreme circumstances. More often than not, this usually amounts to slavery.
To keep a person as though they were property can mean a great many number of things in fiction. Maybe they are hung up in cages like canaries, kept in a glass case with a label or dressed up in bikini to dance provocatively. If the winner knows magic, then their trophy-hood could take on a more literal tone, being turned into a statue of yourself and kept in a hall among other unfortunate hunks of gold and marble. Either way, slavery like this is not maintained out of a need for hands in the fields or for monetary worth, but rather as physical proof that they have defeated you, stringing the loser up and making them look pretty like a shiny medal or blue ribbon.
If this enslavement is mystical in origin, then the only means of liberating oneself of such a deal without serious cosmic repercussions is when the master is dead or finally defeated.
Compare with Battle Trophy, Creepy Souvenir and Dead Guy on Display, which requires the trophy to be dead. See also Deal with the Devil, Human Pet, Living Museum Exhibit and People Zoo. Not the be confused with Lost Him in a Card Game, Trophy Child or Trophy Wife. Can result in Why Don't You Just Shoot Him?
- One Piece: Charlotte Mont-d'Or, one of the pirate Big Mom's sons, has a Devil Fruit ability of "book manipulation"; among other things, he can put living people inside books. Big Mom has him put a lot of unique people and animals inside big books in her palace's library for her collection.
- In Rainbow Rowell's Runaways, the Staff of One is revealed to be an ancient Japanese warlord who lost a battle against Nico Minoru's distant ancestor Takiko. As a penalty for losing, he was given the choice of either dying on her sword or becoming it. He chose the latter, and was transformed into the Staff of One, cursed to serve the Minoru clan until they either all died off or one of them released him.
- In The Unexplored Summon://Blood-Sign, the psychic shock of losing a summoning battle renders people essentially lobotomized for a 24-hour period: they are usually mindless and highly suggestible. Usually this means death or imprisonment for the defeated, but sadistic victors such as Azalea or the White Queen enslave them as Human Pets.
- Enchanted Forest Chronicles: In Talking To Dragons, the evil fire witch keeps all the people she has turned to stone as statues in the courtyard around her invisible castle.
- I Have No Mouth and I Must Scream: After wiping out humanity AM keeps five alive for centuries in order to keep tormenting them. When they manage to kill each other he turns the survivor into a featureless blob with no means of harming himself, hence the title.
- In The Silmarillion, Morgoth does this to a son of Elf-lord Feanor who is captured after losing a battle; he is kept chained only by one wrist to the outer wall of Thangorodrim as for his torment and as a souvenir of victory.
- Doctor Who: In "The Woman Who Fell to Earth", the villain is a Stenza warlord who is undergoing a ritual of leadership that involves Hunting the Most Dangerous Game. The quarry of the hunt is a randomly designated human who must be captured alive without assistance, returned to the Stenza homeworld and preserved in a state between life and death as a trophy.
- Gotham: After Edward Nygma and Oswald Cobbleplot become enemies in season 3, the latter finally emerges victorious over the former after a Gambit Pileup and has him frozen alive by Mr. Freeze. Just to humiliate Nygma further, Cobblepot then has him displayed in his club as a trophy and as a warning to any other challengers to his position. At least until Nygma is unfrozen and starts plotting revenge, although by that point Cobbleplot considers him Not Worth Killing anymore after Nygma has lost his intelligence, making him merely a shadow of his former self.
- Power Rangers:
- Power Rangers Lost Galaxy: in "Mean Wheels Mantis", Motor Mantis transforms Kendrix and Maya into golden trophies after they fail to beat him in a fight, and challenges Damon, Leo and Kai to a motorcycle race if they want them back. They lose, but Leo is able to beat Mantis in a rematch, thus restoring Kendrix and Maya to normal.
- At the end of the Power Rangers Ninja Storm/Power Rangers Dino Thunder team-up episode, Mesogog turns Lothor into an action figure after their defeat at the hands of both Ranger teams.
- In Eclipse Phase at least one crime lord is rumored to have a tank full of koi with cyberbrains storing the Egos of her enemies.
- Warhammer 40,000: Inverted by Lukas the Trickster, who does this do people who defeat him. One of his hearts was replaced by a stasis bomb, meaning that on dying, everyone in base contact with Lukas is trapped for eternity with only his mocking laughter for company. This has since been nerfed, since the first version of this ability allowed him to remove Titans with ease.
- Dungeons & Dragons adventure Q1 Queen of the Demonweb Pits. Lolth once defeated and captured a ki-rin and placed it in a suspended animation cube. If the Player Characters free the ki-rin, it will offer its services to them.
- In the Guilds of Ravnica storyline of Magic: The Gathering, gorgon assassin-turned-Queen Vraska ends up on a throne made out of traitors and enemies she turned to stone herself. It's as comfortable to Vraska as it is deterrent to others.
- The King of Fighters: Whenever he wins a fight, Rugal Bernstein keeps the people he sees as a Worthy Opponent in liquid metal and then put them as statues in his personal ship.
- Mass Effect 2: Aria T'Loak, the ruler of Omega, did this to her krogan predecessor ("Patriarch") after winning the power struggle for the station: rather than killing him, she made him her "advisor" and keeps him around as a symbol of what happens when someone tries anything against her.
- In The Unexplored Summon://Blood-Sign, the psychic shock of losing a summoning battle renders people essentially lobotomized for a 24-hour period; they are usually mindless and highly suggestible. Usually this means death or imprisonment for the defeated, but sadistic victors such as Azalea or the White Queen enslave them as Human Pets.
- In Luigi's Mansion, King Boo holds Mario captive inside a painting. E. Gadd had also done this with the various ghosts of the mansion, King Boo included, like an art exibit. In addition to finding Mario, Luigi's mission is to recapture the ghosts and put them back in their paintings.
- Conan Exiles: Taking thralls works like this. You beat an NPC down with a truncheon, tie them up and drag them home, break them on your Wheel of Pain, then set the doing various tasks for you. There are fighter thralls to help you in combat, bearer thralls to carry your loot, cook and blacksmith and armorer and alchemist and other thralls to help you efficiently craft high-end gear, but the trope is played straightest with Entertainer thralls, who dance for you to remove corruption and improve natural healing.
- Mortal Kombat X: When Predator wins a match and no fatality is performed, he rips off the defeated's skull and spine and puts them in a trophy room with other creatures' skulls.
- In a Bad Future of Jackie Chan Adventures, Viper has been stuck in a cage for the pleasure of the Demon Sorcerer Hsi Wu.
- OK K.O.! Let's Be Heroes: in the "Crossover Nexus" special, K.O., Garnet, and Ben come across an old building turned personal museum housing everyone Strike defeated, turned to stone with a red X marked somewhere on their bodies. They're freed when Garnet reprograms Strike's robot to undo all the damage he did.
- The Powerpuff Girls: In "Collect Her", a Loony Fan of the girls has collected all the merchandise he could find, and is still not satisfied, so he starts stealing their personal belongings. Eventually, he resorts to collecting the girls themselves, trapping them in special Super Packages.
- The Simpsons Treehouse of Horror X feature "Desperately Xeeking Xena" features Bart and Lisa gaining superpowers and teaming up with Lucy Lawless in order to take down "The Collector", who collects people (specifically celebrities) and keeps them as trophies because he feels like it.
- In Steven Universe, the Human Zoo was a private menagerie built by Pink Diamond as a means to contain a private collection of abducted humans to act as living trophies for her conquest of Earth. All modern human specimens there are descendants of said abducted humans. It is later revealed that Pink Diamond wasn't actually the one who built the Zoo, but rather Blue Diamond, who misunderstood Pink's desire to preserve Earth's life.
- In the Teen Titans episode "Only Human", Cyborg manages to beat the robot Atlas at an online game. In retaliation, Atlas goes to Titans Tower with the intent of destroying him in real life. Atlas manages to defeat him and the other Titans before capturing them in bubbles, telling Cyborg that if he wants his friends to be free, than he must agree to a rematch at the Old Stadium. Cyborg agrees and loses the fight, only for Atlas to go back on his word and keep the other Titans as his trophies.
- While real life slavery comes about in a number of ways (debt, violation of the law, being born to parents who are also slaves, being sold into slavery by one's own family, etc), the newly enslaved were usually prisoners of war was a common cause, one group doing battle against another and then capturing the enemy (and their families and friends and other non-combatants from conquered territories) and being kept as personal servants, pleasure thralls and other unfortunate circumstances. Usually they are branded or given an accessory like hand-cuffs or a collar to mark them as their property.
- One of the most known real stories from the Byzantine empire was the absolutely brutal fate of the emperor Nikiphoros Phokas after his defeat in the hands of the Bulgarians. They made his skull into a wine grail.