Rayman: After defeating the first boss, a huge mosquito, it starts crying, and when Rayman pats it on the back they form a friendship and actually work together in the next level.
Command & Conquer Red Alert 2: Happens in the Soviet campaign of Yuri's Revenge when they defeat the Allies and team up to take on Yuri's forces.. and vice versa in the Allied Campaign, although the Soviets using time travel to force a different outcome is much more plot-critical.
Bismark's Furor Teutonicus creates a chance that barbarians will join you after taking their encampment.
The Mongol scenario has militaristic city-states provide you with soldiers when you conquer them.
Final Fantasy games often require you to defeat various monsters as bosses before they offer you their power as Summon Magic.
In Final Fantasy IX, Amarant is a bounty hunter hired to kill Zidane and company, until they best him in a fight and he decides to throw in with them. This is one part honour and one part trying to figure out exactly how he beat him.
In Final Fantasy VII, it's Yuffie, who joins your party after a fight in an attempt to screw you over. Eventually becomes a sincere member of the party after you save her from Don Corneo.
In Final Fantasy VIII, seven of the game's sixteen Guardian Forces are fought as bosses, including the first boss, Ifrit, and must be defeated in a boss fight before you can use them.
In Final Fantasy XIII-2, Most of the monsters you beat (non-boss only) become your familiar and help you in fights.
Final Fantasy Tactics: While several former antagonists join Team Ramza after their defeat, it's usually other factors that lead to them making a HeelFace Turn; however, generic enemies (of both human and monstrous persuasion) can always be persuaded to join the party using the Mediator skill Invite, which has better chances of working after you've whittled down their health a bit—in the case of monsters, you can even have the switch in loyalties happen automatically with the Support skill Train, in which they will come over to your side as soon as the person with Train drops their hit points below a certain threshold.
In the Shin Megami Tensei series if you defeat a boss you can create it through fusion, and this will remain in the compendium even in New Game+ and can be summoned regardless of level provided you have enough money to summon it.
Devil Survivor has the Nintendo DS lookalike COMP, which upon activation summon a demon for you to fight. If you defeat it, it will become your subordinate. And then a fraction of the way into the game, Midori defeats a Jack Frost and teaches him about The Power of Love and Friendship. A few days later, he reappears and depending on your choices, you can recruit him into your party on the last day.
Devil Survivor 2 features Social Darwinists Yamato Hotsuin and Keita Wakui, who believe that Might Makes Right. Both of them will fight you if you take any ending path other than Yamato's, and after you beat them they'll both admit that by their own logic, you've got the might and therefore must be right.
One of the worst aversions of this trope is in Dynasty Warriors Gundam 2. The more times you defeat a character, they will have negative opinions of you and your friendship with them will drop. Since you will need to have high friendship with characters in order to obtain their Gundam, this is a pretty annoying thing and will make obtaining them pretty tedious. But in the third and future games, the friendship with characters will always go up and never go down.
Played with in Persona 4: after each member of the Investigation Team confronts and comes to terms with their Shadow, the physical manifestation of their worst qualities, that Shadow will turn into their Persona, which they can control. The twist is, fighting their Shadows is unnecessary, even though it always happens in the game; if they simply accept that the Shadow was part of them, as they do after the fight, it becomes their Persona.
This is the hallmark of the Touhou doujin game series. The only playable character that didn't start as a boss is Reimu herself. In fact, almost every game ends with the good guys sitting down for tea with the bad guys and unlocking a bonus stage.
It's also heavily implied in the backstory of the goddesses in Mountain of Faith. Kanako defeated Suwako to conquer her kingdom, but didn't exile her and agreed to share the shrine.
One of Reimu's alternate outfits/color schemes in 12.3, Hisoutensoku, is a Shout-Out to the Nanoha herself. Makes sense, as they both are fans of Friendship Through Superior Firepower.
In Touhou Labyrinth, a boss fight with one of the major Touhou girls always ends with the girl (or guy, in the case of Rinnosuke) in question "joining" Reimu's party in the post-battle cutscene. How willing each girl is at the matter varies individually, though.
This trope finally got averted with Double Dealing Character's Big Bad, Seija Kijin, who got the societal upheaval plot of the game rolling by manipulatingShinmyoumaru Sukuna into doing her bidding. As it turns out, in Impossible Spell Card, following the events of DDC, she was branded an outlaw and hunted by everyone for all the shit she stirred up. However, Seija is so contrarian, enemies basically are friends from her point of view.
In Sonic Adventure 2, Shadow is an exception in that he's the one orchestrating the evil, so even after his defeats at the hands of Sonic, he continues to be evil, and his HeelFace Turn comes later in the Last story. Also, this is played straight with Knuckles, who manages to befriend Rouge after he defeats her in a battle, and soon afterward saves her life and earns her respect.
Super Smash Bros. Brawl uses this as a common means of getting new allies in the Subspace Emissary mode. The odd thing is that you can often fight as either, so it works both ways.
In Disgaea, Flonne, Hoggmeiser, Maderas, and Gordon all get converted to Laharl's side after he beats them handily in boss battles. Also, defeating a monster-type enemy makes it available for you to create and use in battle. Killing more and more of the same type results in it costing less and less Mana to summon. If you're impatient and have strong characters not in play on the field, you can also just throw an enemy monster-type into your base panel (where your characters start in a given battle) and, if your reserves can subdue the monster, that monster will join your team assuming you defeat the others.
Disgaea 3's Raspberyl is a big believer in this trope. In the ending to the first chapter of Raspberyl Mode, her advice for making friends is as follows: "First, bust into their house... then, use your passionate fists and fight them till the end. Once the two of you collapse to the ground and start laughing, you guys will always be friends."
All the members of the main cast of Disgaea 4 who aren't with you from the beginning join after being defeated. Tyrant Valvatorez takes this concept to its logical extreme by making it a literal in-game ability - any enemy he defeats becomes a CPU-controlled ally for the remainder of the battle.
In Phantom Brave, killing a few of an enemy type will make it possible to recruit that enemy type.
In La Pucelle Tactics, if you "purify" any enemy before killing it, it will join your party and can be fielded immediately if you don't already have 8 units in play.
In Makai Kingdom, Zetta can challenge and beat most of his fellow overlords and obtain either them or some other form of stand-in (they've got netherworlds to run, after all) as party members — including Laharl — during a New Game+. Just don't expect this to work on Salome, though.
Disgaea 2 has Yukimaru, who joins you after Adell beats her in the tournament and talks her down from probably-very-honorable-but-not-really-wished-for suicide.
Soul Nomad & the World Eaters has Odie as a main story example, and Asagi and Lujei as Bonus Boss examples. The Demon Path is full of this, but it's more a case of 'defeat equals slavery' there — except for the previous villains, who line up to join you with a smile on their faces.
Shar-Teel, in the first Baldur's Gate is less over-the-top version, as she simply insists on dueling a male member of your party before she joins you.
Knights of the Old Republic has you, in one of your early missions as a Jedi, track down and defeat the fallen Jedi apprentice Juhani. After you duel her, you can talk her back to the Jedi path with relative ease. Or kill her, if you're Dark Side-inclined, but that's more than a bit of a waste.
After Jimmy beats up all of the nerds, he says that he did it so they could team up to take over the jocks. Earnest, the leader of the nerds, even says "You have a strange way of making friends!".
The leader of the Bullies clique, Russell, remains a loyal friend to Jimmy after he defeats him in a fist-fight and even remains the only clique leader who doesn't betray him in the game's final chapter.
Saints Row IV features two previous adversaries as prominent allies of the Boss (now the President of the US): Benjamin King, the former leader of the Vice Kings from the first game who was forced to drop his flags after an attempted coup in his organization, now the President's Chief of Staff; and Matt Miller, the leader of the Deckers from the third game, who was defeated by the Boss and likewise forced to flee, now a member of MI-6. In addition, enemies from previous games, like Maero, Phillipe Loren, and Tanya Winters, can be recruited as Homies after defeating them in Loyalty Missions.
Sheena joins you after beating her twice. Regal joins almost right after defeating him. Many bosses often convert to your side as friendly NPC's once Lloyd beats the stuffing out of them. With an epiphany speech tossed in for free.
In Tales of Rebirth, almost every party member is recruited this way for one reason or another.
When you meet Tytree, he's been consumed by his Force after his sister was kidnapped, and beating him up breaks him out of it long enough for the heroes to explain the situation.
Annie attacks you and you have to fight her to tire her out, eventually leading to her joining the party.
Hilda is originally Tomha's Tyke-Bomb, who's only diffused by fighting her twice, once normally and a second time in a berserk state.
Veigue is good at this point, but he and Tytree getting into a fistfight and Tytree finally "winning" make Veigue fully admit the pair are friends and the two develop a better relationship as a result.
With Well-Intentioned ExtremistDuke, the final boss. Yuri and friends beat the crap out of him, then completely forgive him after he joined their cause and helped to defeat the Adephagos. Despite the whole, y'know, attempted omnicide thing]].
With Raven, only the eventual defeat didn't so much cause the friendship as affirm it.
Tears to Tiara 2 Hamil defeats Aemilia, proving to her that there's still hope, that there's people hard at work at fixing what The Empire had let fall to ruin, and that there's people willing to fight for the sake of others. And of course his father was her ally at court. She quite eagerly joins the Party and put her administrative skills to use.
Magic Knight Rayearth: In the SNES RPG, similarly as in the animé, every major antagonist will have a change of heart and join your party, and then leave right before you fight the next major antagonist. Except for Caldina, who lets you hire her for 3000 gold if you want her to tag along, and doesn't tag along if you don't hire her. But Fenrio, Ascot, and Lafarga all join your party temporarily, after they are taught the meaning of friendship, or in some cases, de-brainwashed.
In Ristar, a weird alien kid follows you around stage 5-1 in the background, and at the end of the stage you must beat him in a Snowball Fight. Later on, when you fight the stage 5 boss he helps you by bringing hot pizzas to throw in its mouth.
Both subverted and played straight in Grandia with Gadwin's two duels, the first being an impossible boss fight.
The GBA remake of River City Ransom allows you to recruit most of the gang bosses into your party after you beat them. You can even recruit the old Big Bad to use against the Bonus Boss.
An odd variant occurs in The Force Unleashed: rogue Jedi Master Rahm Kota is defeated and apparently killed by Starkiller in the first mission (he doesn't bite it). Much later, after Starkiller's death is faked by Vader, they run into each other again under Imperial fire, and immediately team up, forced together by circumstance. At first, Starkiller thinks that Kota doesn't recognize him because the latter was blinded in their first encounter, but in the Light Side ending, Kota reveals that he knew who Starkiller was all along; he just went along with the ruse because he could sense that Starkiller had a spark of good in him and needed a mentor other than Vader to bring it out.
Big Boss, as a younger man, seemed to attract a number of allies in this way. Ocelot, Python, and Gray Fox. Though in Python's case, they were already friends before they were dropped on opposite sides of the conflict, and after finishing their fight, they were friends again.
Before founding MSF, Big Boss - still calling himself Snake - ambushed a squad of Revolutionaries in Spain and took out half the unit. As he left, a drill sergeant yelled at Snake to help him kill himself and then tried to suicide bomb Snake's squad because of his Japanese pride. When he passed out from blood loss, Snake saved his life. Two years later, Snake and Kazuhira Miller have opened up Militares San Frontiere.
Kaz: Why'd you save me, your enemy, after I tried to kill you?
Snake: Because you swallowed your pride and fought with everything you had.
Kaz: I just didn't wanna lose.
Snake: You found a way to fight back even in the face of death, even when you knew you were gonna die - That's the mark of a true warrior.
Metal Gear Rising: Revengeance has a villainous example with Samuel Rodrigues. Initially he sets out to stop World Marshall, but joins them instead after being beaten by Senator Armstrong. He tries it again on Raiden, but gets sucker-punched with an I Surrender, Suckers, which only pisses him off more.
Nintendo and Sega were very bitter rivals during the 16-bit era Console Wars, but after an embarrassing defeat with the Sega Dreamcast causing them to give up consoles, Sega now happily makes games for Nintendo's systems.
Devil May Cry has Dante and Lady team up after the former defeats the latter as a boss. The same goes for Dante and Nero, sort of.
More like Defeat Means Grudging Allegiance in MechWarrior 4: Mercenaries; you can challenge a Clan colonel to an honor duel. If you win, she is bound by honor to serve your merc company (as a pilot, so don't get any wrong ideas, mkay?). Your second-in-command calls this out as an unreasonably bad idea, and while Falcon doesn't disobey orders, she's not exactly happy with the whole arrangement.
The Friend Ball automatically makes anything it catches friendly to its owner. Otherwise, catching a Pokemon only guarantees obedience; captured Pokemon will start with a rather low happiness rating.
In the 2nd Gen games and remakes, defeating certain trainers prompts them to give you their phone number, allowing you to call them every now and then, and them to call you for a rematch or give you useful items or information...or just annoy you by telling how they almost caught that Pidgey for the millionth time.
In the 5th Gen games, you can fight and beat Doctors and Nurses on the routes. Once beaten, they will heal your party for free every time you talk to them. Since they tend to hang around in places far away from cities, this is very helpful.
Pokémon XD: Gale of Darkness has all of the Cipher admins become friendly with the protagonist after they're defeated in the post-game Orre Colosseum, sending him a letter to this effect... with one very notable exception. Ardos instead sends a death threat saying the remnants of Cipher will always be watching him, making it clear that he still holds a lot of ill will towards the protagonist.
The fan comic CharCole shows some more reasons for Pokémon to follow their trainers: "Charlie" Cole eventually agrees out of concern for Brian and his other Pokémon, while Raijal's Pikachu, Kraker, apparently just likes to fry some Pokémon butt and be praised for it.
This trope has a major role in Pokémon Mystery Dungeon. After an enemy faints there's a percentage chance that they will want to join your rescue team. How likely this is is affected by the many different aspects, such as level, the Pokémon being recruited, etc. So it's a whole game based on this trope. However, you have to leave the dungeon "successfully" in order to keep them, and not all Pokémon can be obtained this way.
In Pokémon Mystery Dungeon: Explorers, it's changed so all you have to do is beat them. If your party's full, they just teleport out. You no longer have to complete the dungeon with them. Success!
Pokémon Mystery Dungeon: Gates to Infinity goes an extra step and makes the "defeat" part completely optional for most Pokemon. Once you've defeated a species of Pokemon, you'll usually get a recipe for a gift specifically for that species, which when presented to them, will immediately cause them to ask to join your team. However, evolved Pokemon are exempt from this, and some species lack gifts specifically for them, instead requiring a much rarer gift that works on a particular type of Pokemon instead.
The concept behind the captures in Pokémon Ranger is conveying one's feelings of good will to the Pokémon, requesting their (temporary) help in whatever heroic campaign you are undertaking. It's really not as cheesy as it sounds.
The Black/White generation of games hints that most of the wild Pokémon you come across want to be caught so they can get stronger and see new places. An NPC who apparently figures out how Pokemon feel about you by looking at their footsteps tells you that ones that like you fairly well hear wild Pokémon telling them that they've forgotten what it's like to be wild, whereas Pokemon who love you see the wild Pokémon as envious of the partnership.
In Black2/White2, the three Legendary Pokemon Cobalion, Terrakion, and Virizion (collectively called "The Three Muskedeers" by fans) clearly want to battle you. When they each appear, it's as if they were waiting for you to come. Latios or Latias (which one depends on the version) is even more eager to battle you; instead of standing still like most Legendaries do, it actually rushes up to and starts the battle whether you want to or not!
Shows up in PokéPark Wii with a twist — battles are only one of the skill games, with tag and hide-and-seek being the other two competitive ones.
This is one of the ways to obtain additional Pokémon in Pokémon Rumble. The chance of it occurring is normally rather low, but when attacking enemy Pokemon, they have a random chance of becoming dazed and defeating them while they're in this state guarantees that you'll obtain them.
In Battle For Meridell, a game available on the website Neopets, you battle monster versions of the species you can fight as. When defeated, they turn good and fight for you. This also works both ways, as them defeating one of your characters turns them evil (and makes them lose any equipment they were carrying).
In the NES version of Double Dragon III, the bosses of the China (Chin) and Japan (Ranzou) stages join your side after you defeat them. Interestingly, they actually become playable characters, allowing you to continue if Billy or Jimmy is killed or even to temporarily use their strengths (powerful claw punch and speedy ninjato respectively) where most useful.
In Mega Man Powered Up, The Updated Re-release of Mega Man, if you defeat the bosses using only Mega Man's Buster said boss will be left intact upon defeat and be taken back to Dr. Light's lab for repairs, making them playable. Using any other weapon will just destroy them.
This is the standard mode of character recruitment for the Wei campaign in Warriors Orochi, though most of the time it's more "defeat = forced to join your side". Eventually, though, Wei defects from Orochi control and a large chunk of disgruntled ex-Wei officers show up to help. The other campaigns are a mix of this and Big Damn Heroes.
In Star Ocean, if Ratix tries to reach C rank in the arena after a certain plot event, Tinek Arukena will announce that he wants to fight Ratix since he finds him a worthy opponent, then leaps in from the audience bleachers and replaces the end boss for the fight. If you defeat him and has less than eight members, he'll join up afterwards. (If you have no free spaces, he just leaves.)
Marcus the super mutant from Fallout 2 narrates to the player a one-on-one battle between himself and a member of the Brotherhood of Steel. After three days the two combatants reconcile, become good friends, and found a town together. Doesn't quite fit the trope 100%, as Marcus seems to imply that the fight was a draw.
In Cave Story, the protagonist does this to Toroko, Curly Brace, and eventually Balrog. In Toroko's and Curly's case, it's because they preemptively attack him, thinking he's a killer—so by defending himself and not killing them, he wins their trust. In Balrog's case, it's because Balrog is a decent guy, only working for the Big Bad because he's magically forced to do so.
In Team Fortress 2, all Valve (public) servers automatically rebalance the teams in a game if one team wins enough times without letting the other team win by shuffling players between the two teams. (Good luck finding a server where the players stick around after an autobalance and don't promptly quit because they've been shuffled onto the losing team.)
this can happen with Zevran, potentially leading to a romance, as well as Loghain.
Played with in the case of Loghain though; while the player may forgive him for showing remorse as he is defeated, Alistair will most certainly NOT. He becomes infuriated with the player, reminding them of all the evil Loghain has done in the recent past, contrition or no.
This is the stated endgame of the Qunari (a religious force, not a race) - once they've beaten an enemy, said enemy is "re-educated" to embrace the Qun, which is the Freedom from Choice philosophy of the Qunari. Of course, if a prisoner is particularly stubborn, they're just turned into a mindless laborer using a substance called Qamek.
Marvel Ultimate Alliance 2: Deadpool does this after you prove you're not aiding the terrorist attack in his debut level. In the penultimate level you fight Green Goblin and Venom, and when you defeat them to free them from The Fold they go into an Enemy Mine with you, so it sort of counts, though both are very agitated working alongside their archnemesis Spider-Man.
In Rosenkreuzstilette, Spiritia has to fight her friends to get them to listen to her, which is no easy task given they are all magical girls. And then there's Grolla trying to convince them that an "unassuming" child is behind all the madness.
The Suikoden series is full of this trope. There are 108 recruitable characters in each game, and many of them start off as enemies, or simply won't join you if you can't defeat them in a fight. In the first game, 3 of the 4 enemy generals join up after they're beaten, though you do have the option of killing them instead, but this is not recommended as you won't get the "good ending" because you didn't gather the 108 Stars of Destiny.
This occurs once in Valkyrie Profile. Throughout the game, you witness the deaths of heroes, and recruit their souls for Ragnarok. At one point, the Valkyrie is commanded by the goddess Freya to kill a wizard named Gandar and take his soul. After he's dead, he refuses to join up with Valkyrie. She gives him the ultimatum of joining her or being sent to Hell. He grudgingly accepts.
In Mario Super Sluggers, after defeating Bowser in Challenge Mode in his own castle, Mario and his friends invite him to play baseball together for fun. Bowser accepts.
In Paper Mario, Lakilester (AKA Spike) fights Mario on Huff N. Puff's orders. After Mario beats him, he joins his party.
A few of EarthBound's supporting characters are introduced as bosses, even one in particular who helps you defeat Giygas.
In Recettear, Charme gives you her Adventurer Card a few days after she's defeated at Jade Way, allowing you to recruit her for other missions. The same goes for Tielle and Griff as well.
In Banjo-Tooie, Terry, the boss in Terrydactyland, accuses Banjo and Kazooie of stealing his eggs, and they fight him in a boss battle. After Terry is defeated, Banjo says that they haven't stolen his eggs, and offers to look for them for him. After finding them, he thanks them and rewards them with a Jiggy.
Invoked in Golden Sun: Dark Dawn. The spirit of the sentient Sand Prince Gem is enthusiastic in greeting the party characters and happily offers them his/its assistance... but he/it needs them to pass a test of character before they can use him/it.
Inazuma Eleven is chock full of this. Even the most evil people become good by the end of the third games after you have beaten them again and again. Bonus point goes to the fact that you can recruit almost every of them into your team.
Opponents also become allies after they are beaten in Danball Senki, which is from the same creator as Inazuma.
In Sin and Punishment: Star Successor, the Griffin Keeper boss of Stage 5 befriends the main characters after they defeat it, and it offers to carry them to their destination Mt. Fuji.
In Solatorobo, a quest with Alman has him asking Red to teach his new apprentice to work harder. The apprentice wants none of it, telling them to leave him alone, and eventually prompts Red to fight him. Once beaten, his attitude does a 180 and he'll do anything "Boss" Red tells him to, including working as hard as he possibly can.
In Advanced Variable Geo, this is Yuka's fighting style. More specifically, she has the ability to form an empathic bond with those she fights; once she's in tune with their soul, she's able to defeat them spectacularly, and whoever she defeats has a high probability of becoming a fast friend with her.
I Miss the Sunrise has the twist in that you need to fight them twice. Jessamine is fought as a Mini-Boss towards the beginning of His Master's Voice, and can be fought again as a Bonus Boss later. They join your party after that.
In the series' backstory, founder of the Second Tamriellic Empire, Reman Cyrodiil, incorporated the defeated Tsaesci invaders from Akavir into his fledgling empire. After Reman used the Thu'um against them in battle during their invasion of Tamriel, they recognized him as Dragonborn, who the Tsaesci believe to be the ultimate dragon slayers. He incorporated the surviving Tsaesci into his armies, where they served him as bodyguards, dragon hunters, and would be the precursors to the Blades. They also became a great cultural influence within the empire.
There are several NPCs who invoke this trope. When you talk to them, they challenge you to a fistfight. When you win said fight, they become much friendlier and most of them will even join you as a follower if you ask. There is one particularly racist NPC who manages to zigzag this trope, should you challenge him as an Elf. After you defeat him, he will switch between his usual racism, proclaiming you to be a cheater, and this trope, calling you a good friend.
One of the staples of Dragon culture is the belief that the strongest is meant to lead, hence Dragons who survive clashes with another frequently offering their allegiance to the one that bested them. Odahviing and Durnehviir end up invoking this towards the Dragonborn during the main game and in the Dawnguard DLC; the former defecting in the belief that Alduin lost his right to command after he fled battle with the Dragonborn, while the latter does so out of respect for the Dragonborn being the first individual to ever best him in combat. After the defeat of Alduin, many of the Dragons under his command switch their loyalty to Paarthurnax, who leaves to instruct them in the Way ofthe Voice.
In Pirate101 some enemies will join the player's crew after they have been defeated.
Assuming you don't want to use the Classic Cheat Code to unlock him, this is how you get access to Roo in Streets of Rage 3, albeit in a different manner than normal. You have to leave him alone during the brawl against him and his trainer and only defeat the trainer, at which point you can select Roo when you have to use a continue from then on.
This is done twice in the Black Side (Jack Cayman) story in Anarchy Reigns. The first time it happens is with Big Bull, whose fight was supposedly Jack's induction into his brotherhood. As such, Big Bull returns from time to time to help Jack out. The second time it happens is with Rin Rin, who "owes her life" to Jack after he opted not to kill her after beating her. She also returns to help Jack out from time to time.
In the original MLB Power Pros game, when your character defeats the Champion Rings in Success Mode, and subsequently their ace pitcher Zero Gibson, Zero learns about friendship from your character, and Zero "appoints you" to be his friend, which gets a deadpan reaction from your character.
Multiplayer games with auto-balance have a form of this. Is your team outnumbered by at least two players? The next enemy one of yours takes down will defect to your side.
In the Revelation route, this how Camilla (the Avatar's eldest sister on the Nohr side) and her subordinates, Beruka and Selena, are recruited. She is sent by Garon to stop the Avatar and Co., alongside her Amazon Brigade plus Flora, and says she really doesn't want to kill the Avatar, but that if it has to be done, she'll do it herself, otherwise, she will be executed by Garon for failing or refusing. At the end of the level, after defeating her and Flora, she asks the Avatar to kill her, but the Avatar refuses and she and her group join in (save for Flora, who returns to the Ice Tribe, who have already gone into hiding).
In Birthright and Revelation, this is how Silas is recruited.
In the survival / colony simulator RimWorld, if your survivors take prisoners from an attack on the colony, these prisoners can potentially be recruited into the community.
Mass Effect 2 has a small one with Grunt. When he's awakened from his tank, he immediately attacks Shepard and pins him/her to a wall, demanding that s/he give reason to command him, not expecting much from a human. Revealing the kind of enemies s/he has and that s/he has had a gun on him through their entire conversation impresses Grunt enough that he pretty much instantly gains Undying Loyalty to Shepard.
Also turian standard policy. When the turians win a war, they absorb the defeated enemies' population and territory into their empire and recruit them as auxillaries for their armies. At the conclusion of their service they're granted full turian citizenship with all the accompanying rights and responsibilities.
In Toy Commander, after you defeat one of the seven generals, said general becomes playable in the final fight against Huggy Bear.
Several recruitable characters in Exit Fate, both optional and mandatory.
After you rout Keyser's forces with a gambit thought up by Bast and take him prisoner, Bast approaches Keyser and asks him to join your side. To his credit, Bast does make several good points to entice him: Keyser is now disgraced in Kirgard and couldn't go back to his old life anyway, Zelmony is proving to be the winning side, and best of all, "Don't you want to see what you and I can accomplish together?"
Vanrushal the vampire joins you after you've defeated him and taken away most of his power. He does this of his own accord, both for his own safety (since he's much weaker now and his mansion is full of deadly monsters) and because you seem interesting. You don't even get a chance to refuse.
Deke joins after you defeat his prototype robot. Obviously, this means that he still has much to learn and far to go.
Daniel attempts to invoke this with Pereious after routing his forces in battle several times. He fails to sway him, but Pereious still at least gives Daniel advice with how to deal with the Almenga army.
Undertale both subverts and plays this trope straight. You can befriend any monster you encounter(including bosses) after winning the battle. The catch is, to do so you will have to "win" the encounter by non-violent means. If you will fight the monster, the battle will end with you actually killing them.
In Pocket Arcade Story, Rivals who've lost to you in tournaments will immediately become patrons your arcade.
Elena from Street Fighter III basically takes this as a policy since she isn't fighting as a matter of personal pride or glory. Instead she uses it as a way to meet new people and befriend them, strange an approach as it is.
A literal example in One Night at Flumpty's. What is your reward for beating Hard-Boiled Mode? You get to become Flumpty's new best friend!
Hyrule Warriors. In Adventure Mode, King Bulblin appears in some battles on the Twilight and Termina maps and Captain Keeta appears in some battles on the Termina map. They appear as part of the enemy or rogue forces but will become your allies and fight on your side if you get their health low enough.
In Rabi-Ribi, Erina and Ribbon have to invite magic users to come to Rabi Ribi Town to help with a more worrying problem. The problem is, any time Erina tries to strike up conversation with such an individual, that person usually either attacks Erina over a misunderstanding or is Brainwashed and Crazy by a "bunny phenomenon" and has to be snapped out of it by defeating them, with few exceptions. In any case, defeating the target usually gets them to come to town, though two bosses have to be fought multiple times for it to succeed.
In Tekken 4 and 5, King fights and beats Craig Marduk, who murdered Armor King in a bar brawl before Tekken 4. After the second defeat, Marduk decides to change his ways and become a more honorable fighter when King forgives him and the two end up as tag-team partners in the professional wrestling circuit.
In The XCOM Files if you capture an enemy dog alive, it's added to your kennel.
At one point in Ice, John and Kanyenke defeat a small British force and then recruit the troops over to their side to fight in the next mission.
Exaggerated in the case of the Chinese explorer, a Shaolin master who has a chance to convert any opponent he kills into a special Disciple unit. This can include wild animals.
Talon of League of Legends was only bested once in battle, when the fearsome General Du Couteau sought out the assassin making a name for himself on the streets. After being bested, Talon swore undying allegiance to him. And him alone. Even after his mysterious disappearance, Talon still carries out his Noxian diplomacy in his name.
At the end of the Ensemble Stars! Main Story, when Trickstar overcomes fine in the DD, Eichi admits to Subaru that he might be starting to feel something like friendship for him. This is also something of the theme of Quarrel Fes, where Eichi insists on he and Keito fighting one another face to face, because he's worried that Keito is giving up his life for Eichi and wants to prove that he sincerely wants to be an idol and isn't just wasting away here. Only by Keito beating him can the two overcome that tension in their relationship and become fully equal friends.