Enemy Exchange Program
In RTS games, at least the kind where the sides are significantly different from each other, it will often be possible to capture structures that produce enemy units and make enemy unit types for your own use. Pre-scripted single-player scenarios will sometimes make this mandatory or even restrict you to only using enemy units for the duration of the mission. This is an obvious way to add variety, but can easily come off as contrived story-wise. A variation of this is having units that can take control of enemy units during battle. Compare Monster Allies.
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Real Time Strategy
- Possibly the oldest game that does this is Populous II, which allows you to place "baptism fonts" with water magic, which convert troops from one side to the other (and back). The prequel, Populous: The Beginning (the earlier Populous games are god games, and this one is a straight RTS where the plot involves becoming a god) has the enemy-converting priest as one of the basic troops.
- The Command & Conquer games did this so frequently that it sometimes becomes a quick-victory tactic. The oldest and most common method was to send an Engineer into an enemy building, allowing you to produce side-specific infantry and equipment with it. Newer games brought newer methods. Tiberian Sun introduced abandoned vehicle hijacking, Generals expanded this to include killing the pilots of enemy vehicles, Red Alert 2 had varying strengths of wireless mind control, and as of Command & Conquer: Red Alert 3, there's bribing.
- Certain scenarios can also trigger capture in ways that are not conventionally possible. For example, several times in the Tiberium series, Nod stole a GDI Ion Cannon by cracking into GDI's network infrastructure. Another type of scenario-triggered capture happens in the Red Alert: Counterstrike mission, "Sarin Gas: Down Under": an Allied Spy can hijack vehicles by infiltrating Soviet War Factories.
- Quite possibly due to software limitations, unit quotes from Red Alert and beyond can be quite jarring if they are side-specific like, say, a GDI commander producing a Nod Militia squad whose one of many lines is "Down with GDI!" or an Allied commander's Ant whose response is "Vehicle reporting." Granted, the last one isn't so much Enemy Exchange, as much as it is a Game Mod.
- In the Age of Empires series, an extremely ridiculous example was the single-player campaign in the expansion pack for Age of Empires II, in which you played Aztecs defending against the Spanish invasion. In the final scenario, completing certain objectives would give you some Conquistador units (the Spanish special unit: mounted musketeers wearing plate armour) and a Turtle Ship (normally available only to the Korean faction).
- Within the normal game, I and II have Priests, which can convert enemy units.
- Age of Mythology mostly averts this, but in the expansion, playing as Kronos or Gaia gives you the choice of worshipping Rheia, who provides you with the Traitor god power, which lets you take permanent control of an enemy unit. However, you only get two uses of said power.
- In Dune II, the Ordos faction's "Deviator" tank could temporarily turn enemy units to Ordos control.
- Capturing an enemy factory allowed you to build that enemy's "unique" unit (Atreides sonic tanks, Harkonnen Devastators, etc).
- Weirdly, combining the above two examples did not work as you would expect. Some versions (and mods) allowed non-Ordos to capture an Ordos factory and produce their own Deviators, but no matter who owned the Deviator, it always turned its victims to Ordos.
- Of course, taking over a unit for as short a period as you could didn't really do that much good...except against Devastators, which could be ordered to self-destruct.
- This is a major component to Z where you have to capture territory to gain additional factories to create your robots. Slightly annoying as the clock doesn't reset when the territory has been captured; meaning that heavy tank that took 5 mins to build and was just about to be completed before you lost the territory is now in the enemy's hands. You can use this against them too, setting the factory to build the weakest unit just before losing it. Probably justified as they're robots, all they need is slightly different programming to switch sides.
- Z Steel Soldiers has an early level were plot-wise you're attempting to build up your forces and technology (as command hasn't sanctioned your actions) by using a hacker to take control over a small enemy base before assaulting the larger one. In general gameplay the hacker can be useful but they're weak and easily destroyed by gun-emplacements.
- It's possible to do this in Warcraft II according to technical mechanics, but it's not a situation that ever occurs during campaign mode. In custom scenarios, it's possible to confuse the game's soundbytes by abusing the mechanics, resulting in the Command & Conquer situation where human footman would start grunting like orcs.
- The expansion for Warcraft II, however, had such scenarios in each campaign (Alliance and Horde).
- In Warcraft III, the Undead Banshee unit can possess a single enemy unit, sacrificing itself to give you control of it. The Death Knight hero can temporarily raise up to 6 dead units regardless of former allegiance to fight for him, although without any special abilities or spells that the unit might normally have.
- It should be stated that in the campaign, although normally possessing a builder with a Banshee locks out their building capabilities, the High Elf worker which appears in the same Campaign mission where the Banshees are introduced does not, meaning you can then begin constructing their structures and, therefore, units. In freeplay matches online or versus computers, there is no such restriction.
- The Expansion added the neutral Dark Ranger hero, who can permanently take control over a single enemy unit, abilities and all, every few minutes.
- Blood Elf Spell Breakers can convert summoned units.
- In Starcraft, the Protoss Dark Archon has a Mind Control ability that can capture enemy units and convert them to your side. If it's used on an enemy worker unit, you can then use it to build that race's units - and since the three races all have separate Arbitrary Head Count Limits, it is then possible to raise up 200 units of each race in your attack force.
- Additionally, the campaign editor lets you set any unit to "rescuable"—including units whose race doesn't match the player's (or you can cut to the chase and implement triggers that give players units of other races, either by spawning in additional units or changing control of existing ones). The first game, where Dark Archons weren't available, makes use of this in the official campaign. In the final mission, you control two races (the Terrans and Protoss) at the same time.
- The Zerg get an aversion though: an infested command center is acquired by beating an enemy command center to the red, then getting a Queen unit to the building before it explodes. For your trouble you get an entirely different building that makes Infested Terrans, a unique unit which is also far different from what a Command Center usually produces.
- In StarCraft II there is an achievement called Zerglot. While playing as Zerg against a Protoss opponent, use an Infestor unit's mental parasite ability to take temporary control of an enemy probe, which is the Protoss worker unit. While the probe is still under your control, build a Nexus, the Protoss Command Building. Then continue building Protoss buildings with probes built at the Nexus until you can build a Zealot, and then build it. This earns the Zerglot achievement. It is possible to do this in any game mode, but playing against the AI makes it much easier. It is also possible to do this with Terran units by capturing an SCV, but it will either have to be captured again by different Infestors, or multiple ones will have to be captured sequentially to build a Command Center.
- In Total Annihilation both commander units can capture enemy units, including construction units. Core has a resurrection unit that can raise enemy units. In the sequel, Total Annihilation: Kingdoms Elsin, the Aramonian monarch, can resurrect enemy units and Zhon's Harpy and Taros' Mind Mage can capture enemy units.
- In the Spiritual Successor, Supreme Commander, any unit that can build or repair can capture enemy units and structures, though is generally easier to just salvage them. Becomes extra fun when you manage to steal an enemy's engineer when they're a different faction to you. Since a single engineer with some resources can construct everything needed to make an entire army, one can then build practically ANYTHING normally reserved for your enemies with a bit of time.
- Supreme Commander 2 has a mission where an an AI has gone insane and builds engineers and turrets nonstop. Staying in control of your base is surprisingly hard until you get the hang of it.
- The same applies in the Dungeon Keeper series, where enemies can be converted in the torture chamber, but neither they nor your creatures will enjoy each other's company, and will likely require separate dungeon areas.
- They each have a set enemy. Whilst they won't enjoy being in the company of most of your units they can tolerate it, if you keep them well fed and amused. However, if you put a guard next to a dark mistress, the lady who tortured him, expect conflict.
- Also used in the single-player campaign in World in Conflict. There are several missions in which you can take control of abandoned enemy units by repairing them, though this isn't possible in normal gameplay.
- There is also a ludicrous mission in which Soviet special forces have seized control of the Statue of Liberty, Ellis island and Governor's island. They use a large number of captured US vehicles against the player. One character lampshades this by remarking that the number of vehicles available to them is very high, and another replies that the post was oversupplied and undermanned. It is not explained why these islands had any heavy vehicles on them at all.
- Age of Wonders is another TBS fantasy game that allows you to mix units of any faction once you capture a city of theirs, but it generally causes issues due to morale penalties if you try to mix different alignments. Units might abandon your cause, and cities might rebel unless a sufficent force is garrisoned in it. However, the game also gives you the option to convert cities to allied races or just pillage and burn them.
- Globulation is an extreme example, as converting all enemy "globes" is a more standard way of winning than killing them.
- Seven Kingdoms allows you to easily reproduce each race's buildings and units, with the exceptions of the powerful Seat of Power, which can only be built if you have the respective scroll (and each human nation starts with only one). However, human players can't build any of the demonic Frythans structures even if they control some of their units, but it works the other way around. (Getting a large enough number to operate the structures is another issue entirely, as well as keeping them from rebelling).
- Homeworld has the Salvage Corvette that can pick up small enemy craft or latch onto larger ships and drag them back to your Mothership, where presumably the enemy crew is subdued (or worse). The enemy ship is then re-launched with a friendly crew, allowing you to control it. The Game Breaker is that this allows you to exceed the Arbitrary Headcount Limit, potentially giving you a fleet far larger than you could possibly build on your own and making later levels trivial.
- Over-using the Salvage Corvettes can lead to problems in the last level of the single-player campaign. In a previous level, you are faced with a large number of enemy ion cannon frigates. By themselves, ion cannon frigates aren't dangerous to fighters and corvettes, so you can fairly easily capture one. Then rinse and repeat. However, once the final mission starts, you are immediately besieged on three sides by a force whose strength is directly proportional ton yours. So if you happen to have captured 30 or so ion cannon frigates, thinking that this will make your endgame a cakewalk, you will quickly find yourself overwhelmed by a much stronger enemy force.
- Homeworld 2 also allows for capturing with the Hiigaran Marine Frigate and its Vaygr equivalent. The frigate flies up to an enemy vessel and launches a boarding party to take over the ship. However this is much less useful than in the first game as it's a lot harder to capture enemy ships since the marine frigates are easily killed, not to mention that any ships you've captured will lose their upgrades and you you can't bypass the unit cap.
- Played straight and averted in the Warlords series. In the first two games, once you occupy an enemy city (without pillaging or sacking it) you can produce any units that the enemy could in that city, including special units that are specific to the enemy side and otherwise unavailable to you. In the third game captured cities cannot produce those special units unless your side is already capable of doing so.
- Averted in Warlords Battlecry 2, whereas the hero can convert enemy buildings, but the buildings can not be used to build units. They add to your army limit though.
- Warhammer 40,000: Dawn of War: Dark Crusade introduced the Necron Lord Destroyer, which could "possess" enemy vehicles and convert them to your side. When these vehicles are destroyed, the Lord Destroyer pops out damaged but "alive". Seeing as you could only build a maximum of two of these, though, using this is situational.
- Halo Wars gives the UNSC access to SPARTAN Super Soldiers, who have various abilities. One of these includes the power to hijack enemy vehicles, just like they can in the Halo FPS games. They can't capture "elite" units such as the Vulture gunship (UNSC), which is an air unit anyway, and the Covenant Scarab (which is normally controlled by many beings).
- Averted in Star Trek: Armada: to capture an enemy ship, it's shields must be disabled and then boarding parties must be beamed onboard, taken from the capturing ship's crew complement. The boarding crew will invariably take casualties as well, and ships have a minimum crew requirement before they will operate at full efficiency. The Borg, however, play it straight by holding ships in a tractor beam and transporting the enemy crew off to be assimilated, though they can also capture ships the 'standard' way.
- Also played somewhat straight in that capturing an enemy construction ship allows you to access the entire tech tree and build a complete fleet of ships of the construction ship's original race. They will, however, be crewed by members of your own race, often with hilarious results such as a Romulan-manned Borg cube responding with, "Warbird reporting..." when selected because the sound bites for a given unit type (in this case "battleship") are simply transferred straight across (in this case from the Romulan Warbird to the Romulan-manned cube) to all "battleship" type units manned by your race without regard to whether they are fitting or not... Also, by the way, only the Borg's Assimilator unit transports the enemy crew off their ship to be assimilated (where they are either added to the Assimilator's crew or added to your general crew pool if the Assimilator has a full compliment) and it does not actually hold the enemy ship in place. The Borg cube's holding beam does hold enemy ships in place, but it just does exactly what the transporter does except on a larger scale (more Drones are transferred per second than with the transporter) and able to do it through enemy shields... Incidentally, capturing an Assimilator as another race does not remove its special ability. This has the hilarious side-effect of having, say, a Federation-manned Assimilator "assimilating" enemy crew, including the Borg player you stole it from in the first place.
- The sequel averts this with the Species 8472, which have all their bio-ships piloted by a single being. They're also immune to assimilation. Played straight with everyone else. In fact, the game introduces raider ships, whose function is specifically to capture enemy ships. They have a special type of attack command that fires weapons at the enemy until their shields are down and then starts transporting elite marines aboard. A Klingon ship also has boarding pods that bypass shields.
- Warzone 2100 had the NEXUS link turret, which infected enemy units with a virus that made them fight for your side. Somewhat subverted that in single player, it's mostly the enemy NEXUS faction using it on you, and by the time you research the link turret yourself, NEXUS has the Resistance Circuits tech (also obtainable by the player) that makes the link turret ineffective.
- Star Wars: Galactic Battlegrounds has Jedi and Sith Knights and Masters (well, Sith Lords anyway) who can convert units and buildings. Of course, because 75% of the differences between the sides' units are cosmetic, this is only really useful for stealing unique or expensive units, protecting the Jedi in question, or taking advantage of racial special abilities such as the Gungan frigate's ability to submerge.
- Machines Wired For War features allow you to take over enemy buildings as well as steal unit design plans, also the Judas warlord that can convert enemy units to your side.
- Done in Aztec Wars. In fact, constructing some of your own units requires a building that can be only built by an enemy nation.
- In Rise of Nations, the Spy is capable of converting enemy units to the other side using the ability Bribe. However, the normally invisible Spy is revealed after the ability and is partially revealed during the casting (usually during this time they are insta-killed by the Counter Intelligence ability). Apparently, the vanilla Rise Of Nation had the Russians produce spies that don't reveal after using Bribe, so it was kind of a Game Breaker.
- 8-bit Nether Earth may be the oldest example. The whole plot of the game is about capturing alien bases and factories to build robots to capture more bases and factories to kick aliens off the asteroid.
- In Company of Heroes, many weapons like mortars and heavy machine guns require crews to operate. If your troops manage to kill the crew of a weapon without destroying it, they can pick it up and turn it against its original owners.
- In the Hegemony Series, every city has a culture and can only recruit units of that culture. They'll cost extra, but you'll have enemy units.
- Men Of War thrives on this trope. Every vehicle requires a crew from one to five soldiers. You can shoot down the crews of machine gun emplacements, mortars, field guns, and artillery, obviously. However, you can also force crews out of tanks with a well placed shot or anti-tank grenade (if it disables the turret), then repair it, put in your own crew and turn it loose on the enemy. In case of open-topped vehicles, you don't even need specialized munitions - simply chuck in a standard frag grenade. The series should be called Grand Theft Tanks, to be honest.
First Person Shooter
- None of tanks and helicopters in the Battlefield games spawn locked, so although each side has their own vehicles, you need to rely on the color of the player's name above the vehicles to determine which vehicles to shoot at.
- Ditto with Star Wars: Battlefront. Although vehicles that double as command posts like the AT-AT are off-limits to the other side, everything else is fair game. In the second game you can even use an Engineer's fusion cutter to boot out a tank's occupants in order to take it for your side. This gets particularly ridiculous with the CIS, since most of their "vehicles" (including all of their starfighters) are different models of droid, and thus don't have an actual pilot. And yet, the Republic's clone soldiers can drive or fly them just fine.
Massively Multiplayer Online Role Playing Game
- In the MMOFPS PlanetSide 1, each of the three empires has several unique vehicles that only they can build. However, capturing both of said empire's home continents allows the conqueror to freely build those empire-specific vehicles. For example, a Terran Republic player could build, say, a Vanu Sovereignty Magrider and a New Conglomerate Peregrine if his empire is currently in control of all three empire's home continents. Players with the Advanced Hacking certification and a REK tool can hack enemy vehicles to their own side - and simultaneously kick out the occupants - allowing them to get in a gun to wreak havoc, or more commonly, just deconstruct it to prevent the enemy from re-hacking it.
Role Playing Game
- The Elder Scrolls IV: Oblivion lets you summon various daedra and other such things that would normally be enemies. But they turn on you if you attack them enough.
- In also features limited duration command spells that get enemies to fight for you.
- The tabletop RPG Dungeons & Dragons allows evil-aligned clerics (as well as neutral-aligned clerics of evil deities and) to use the Rebuke Undead ability to permanently take mental control over an undead creature. This doesn't work any more as of fourth edition.
Turn Based Strategy
- Sid Meiers Alpha Centauri introduced native Mindworms to replace the barbarians of the Civilization games. However, players could also capture Mindworms and even breed their own.
- Master of Orion II had several features centered around capturing alien ships and populations. Capturing Antaran ships in particular would provide a major technological advantage. Some players would even exterminate their own population units and replace them with captured aliens that had superior environmental tolerances or resource-production!
- While there a few provinces in Medieval: Total War that specialize in a unit and will produce them for anyone, most troop types are tied to the factions. So if your English crusader army captures Egypt the locals suddenly figure out how to grow yew trees in the desert but forget how to herd camels.
- The British campaign in Medieval II Total War: Kingdoms changes this to allow you to recruit this provinces native units for as long as the native culture is dominant there. After it is assimilated into your culture, it can only produce your normal units. This gives you a choice of whether you want certain cool units you can't normally get with the risk of rebellion in the province or safety but losing out on the units.
- In the Heroes of Might and Magic series, you can start training new troops to reinforce your army the moment you conquer an enemy city, so even if you have an army of do-gooder forest elves, you can still add Demonic Invaders or The Undead without anyone trying to gut the enemy they've hated for generations. That said, mixing creatures of different alignments under the command of one hero gives them morale penalties.
- The fifth game in the series hangs a lampshade on this. There's a scenario where the demonic commander captures some forest elf cities and builds an army of elven troops. He then has a limited time in which to capture a demonic stronghold before the massive and predictable desertion rate leaves him with no forces at all. The same character later turns the other heel and finds that demonic forces will thereafter destroy their own cities rather than let them fall into his hands.
- Space Empires IV allows a player to capture enemy ships, steal enemy blueprints, and reverse-engineer enemy technology. So it's downright easy to get someone else's ships—though only capturing them outright will produce ships that follow the enemy design.
- Lords Of Magic has multiple ways of doing this. You can trade with other factions so long as your relations aren't too bad, and one thing that can be traded for is their units. Liberating a faction's Great Temple while they're neutral or better gives control of the faction to you. There are villages on the borders between two factions' starting places that can have a barracks, mage tower or thieves guild of either faction built there. Finally, capturing a capital city gives you control over its unit producing buildings. As long as they haven't been demolished they also retain any training they've already received, although even a max-level mage won't know any spells until you research them for yourself.
- While it's by and large not possible to do this in Battle for Wesnoth (although the Walking Corpses created by the plague ability some units of the Undead faction have will sometimes reflect their origins a bit), capturing enemy villages is a key part of the game because it means that their gold and support now goes straight to you instead of your opponent, directly allowing you to build up your own army more quickly while hampering their ability to keep doing so in turn.
- In Operation Flashpoint and its spiritual successor, the ARMA series, you can literally use any vehicle that isn't locked, so this can and does happen. The Resistance expansion campaign puts heavy emphasis on capturing enemy equipment and weapons to outfit your militia, with captured gear being retained in subsequent missions. One mission even involves an attempt at stealing several enemy tanks.
- Boarding and capturing enemy ships in Master of Orion can yield valuable technology when you scrap them if they have systems or weapons you haven't researched.
- Many of the leaders your can hire come from races you may be at war with. This never comes up.
- An interestingly version of this occurs in Achron: The CESO Heavy Tank has the ability to infect enemy units and structures with nanites. The subverted units still retain the colour and the ability to take orders from their original faction... but you can give them orders whenever you want to too. Instant spies and/or traitors!
- Sword of the Stars have boarding pods that can be used to take control of the guns of enemy ships, turning them into immobile weapons platforms for your side (presumably, the bridge crew disable the ship's central control before being overrun). Ships 'captured' in this way are destroyed at end of combat.
- In Mount & Blade, most units are recruited from villages. These villagers are then trained into the specific soldier class of the kingdom they belong to. However, their birth does not change, even if the country that rules them does. Therefore, it is possible to hire recruits of an enemy nation's soldier type once you conquer parts of their kingdom. There are also a few more complicated ways, such as capturing them in battle, crushing their morale, then offering them a second chance by joining you.
- In Cossacks: European War, you can capture an enemy peasant (or artillery piece, or civilian building, or military building under special circumstances) when your military units are nearby and the enemy's aren't. Enemy peasants however, retain their home nationality, allowing you to build up their tech tree as well as your own. This is less useful than it first appears though, since not one single piece of research you've done crosses over, requiring you to build the new civilisation from the ground up.
Non Video-Game Examples
- Paranatural: Welcome to Hitball ('Cause your wimpy parents banned Dodgeball - dodging wasn't the most important part anyway)! Now sit down while you're sitting down and take notes from Coach Oop about the Golden Switch:
Oop: Only thing happens when ya catch this puppy is yer WHOLE TEAM gets OFFA THE BLEACHERS an' BACK IN THE GAME. NO. BIG. DEAL.
Isabel: Why would we ever throw it at the other team then, Coach Oop?
Oop: Good question, you impatient buffoon. Score a clean hit with the Golden Switch, an' the chump you bonked SWITCHES TEAMS. Lil' tip: AIM FER THE ENEMY'S ACES.
- During World War II, this was an integral part of German war strategy. On field level, German forces often captured and used enemy tanks, cars, and cannons (even horses were used). But it was also extended to larger scheme with strategical resources: Germany produced most of light tanks in Czechoslovakia, and heavy tanks were produced in France, after both lands were captured. Also additional planes were constructed in the Netherlands' existing factories, not to mention Austrian ones, which supplied antitank cannons. This explains how Germany was able to fight successfully against Allies while having much less resources.
- The Soviets did the same — the 5th Guards Tank Brigade even got their first T-34/85 by capturing it from the Germans who had previously captured it from some other Soviet unit.
- The Wehrmacht made heavy usage of captured enemy equipment, particularly against the Soviet Union due to the inability of Germany to provide enough arms, particularly submachine guns and semiautomatic rifles to give its soldiers sufficient firepower to face the Zerg Rush. This eventually led to the logistics becoming a quagmire, since each gun would only work with its own ammunition (German and Soviet guns only had one caliber that was technically interchangeable - 7.63mm Mauser versus the more powerful 7.62mm Tokarev - but they kept capturing and using guns of any caliber from every enemy nation), and likewise, each engine could use only its particular parts.
- The Nazis also recruited a sizable amount of soldiers from the occupied territories. Volunteers, that is. If they hadn't been so blindingly stupid (and, you know, racist), they would have had a much easier time in the Soviet Union, where they were initially welcomed by the populace. Though they were not necessarily volunteers. Stories exist where the 'volunteers' turned side at first sight of Allies.
- The Waffen-SS was the only branch of the Wehrmacht which recruited outside Greater Germany. A great deal - perhaps a full half - of the SS was non-German when the war ended. The last troops defending the Reichstag were from a French SS unit.
- The story of Yang Kyoungjong, a Korean recruited into the Japanese army who was captured in Manchuria in battle against the Soviets in 1938. After spending four years in a Soviet labor camp, he was then pressed into the Red Army to fight the Germans. He was then captured in Ukraine by the Wehrmacht and sent to occupied France. On D-Day, he was then captured by American forces and sent to a POW camp in Britain. After the war, he settled down in America.
- During the Yom Kippur war the Israelis captured many of the Arabs' T-55 and T-62 tanks which were abandoned by their crews. The tanks are still being used by the Israelis in some modified form to this day.
- Both sides used captured enemy equipment for various uses during WWII. This could include simple R&D (the Americans studied captured Japanese equipment to figure out and exploit their weaknesses) or repainting them in the appropriate team colors and using them for recon or combat (the Luftwaffe would use Allied aircraft painted in German markings for recon, knowing the Allied aviators would hesitate to fire on them, while the Japanese military used a handful of captured American P-40 Warhawks in combat).
- During WW1 the British first deployed the Mark 1-5 tank on the Western front. However this tank was regularly abandoned by its crew in the next counter-attack (as it was a deathtrap when not used during an assault) which resulted in the German army getting nearly twice as many battle-ready tanks from battlefield capture than from their own factories.
- The Ottoman Turks used janissaries, who were originally forces composed of enslaved christian children trained to fight for the Ottoman side.