Secret characters are special opponents who are usually not found within the original 1P and 2P Tournament/Battle Plan. To reach them, one must meet specific conditions, often challenging ones in order to face them in kombat. Secret characters often appear as color palette swaps (usually ninjas) of existing characters with enhanced speed and powers. Mortal Kombat is exceptional, if not well-known, for being the first game to introduce secret characters in fighting games, and since then, has become a very recurring trend in the genre. For the most part, secret characters are unplayable and merely exist to challenge the player.
However, in MK3 and its updates and ports, secret characters can be unlocked for player control via the Ultimate Kombat Kode (UKK). If any one of the kodes are input successfully, the arenas will quickly flash by in succession before displaying the character that was unlocked according to the code announcing, FROM THIS POINT ON, I AM AT YOUR CONTROL. Ultimate Kombat Kodes require inputs from both players because of the combined slots.
List of Secret Kombatants
- Reptile: The very first ever secret character to appear in a fighting game, appearing as a 'fused' color palette swap of Scorpion and Sub-Zero. Reptile possesses the moves of both ninjas, along with increased speed. To reach him, one must earn a Double Flawless Victory without blocking once and then perform a Fatality. In addition, the player must be at the Pit stage and a flying object must appear in the background, sailing in the sky past the moon (witches or Santa Claus). The shadows do not always appear, at random. After conditions are met, the player will be transported to the Pit Bottom and face Reptile there. He is only available in certain versions of the arcade game, and all home versions.
All secret characters fought here are fought at Goro's Lair from the first game.
- Smoke: First appearing in MKII in his first canonical human appearance, Smoke appears as a silver palette-swapped version of Reptile, having access to Scorpion's Spear attack as well as enhanced speed. Smoke's defining feature is the constant amount of his namesake emitting from his own body. In addition, his speed appears to be considerably higher compared to the other secret characters, almost as if he is running at times. To reach Smoke, one must press Down and Start when Dan Forden pops up from the bottom-right corner of the screen and shouts Toasty!!. This must be done at the Portal stage to work. When this happens you will be transported to Goro's lair.
- Noob Saibot: A mysterious ninja who would later be revealed to be the original Sub-Zero. First appearing in this form, Noob Saibot appears as a completely black palette-swapped version of Sub-Zero, also having access to Scorpion's Spear. Because of his shadowy palette, it is difficult to track him down in obscure sections of the stage. To reach him, one must accumulate a grand total of 50 wins in a row (25 on the Sega Genesis/MegaDrive) in 2 player mode.
- Jade: A mysterious female ninja making her debut in MKII. Jade appears as a dark-skinned, green-colored palette swap of Kitana, having access to her Fan Throw attack. Aside from enhanced speed, Jade is also immune to any and all projectiles thrown at her as they will fly right through her. To reach her, one must fight in the single player tournament and fight all the way to the match before the ? slot. In this match, the player must win the battle using ONLY the Low Kick and cannot use any other button (including blocking).
- Smoke: A robotic version of Smoke, after his rebellion from the Lin Kuei with Sub-Zero. Here he appears as a blue palette swapped version of Sektor. As with his human form, he still possesses the Spear attack, but it is fired from his chest cavity instead, similar to Sektor's missiles and Cyrax's bombs and nets and has Sektor's teleport punch in addition to possessing invisibility. Unlike the previous games, Smoke is not only fought during the game, but can be unlocked by entering the Ultimate Kombat Kode at the end of the game. He can only be highlighted when the Dragon Symbol rotates to reveal his portrait which happens every three seconds or so. In the MS-DOS version of MK3 he can be played by starting the game with a specific parameter.
- Noob Saibot: He makes an appearance once more. However, his appearance has been altered, resembling a completely black palette-swapped, version of Kano, as no ninjas exist in the game. He has no special moves but still has enhanced speed and some of his combos. To fight him, the Kombat Kode 769-342 must be entered. Once the round has concluded, the winner will be transported to Noob Saibot's Dorfen where he is fought.
- Human Smoke: Smoke's original human form before the Lin Kuei took away his flesh. Following extensive automation, the human form of Smoke exists only in memory. He appears as a faster white palette-swapped version of Scorpion and Ermac having access to the former's Spear and a mix of their combos and a teleport punch. He can be both fought at the end of the game via Shao Kahn's Treasures and accessed in playable form via a code while playing as Robot Smoke before the round starts. Holding Back, High Punch, High Kick, Run and Block is the combination. Once transformed, the player will remain as Human Smoke throughout the tournament until either they lose in any match or win the final battle.
- Human Smoke is also playable in the iPod, iPhone, and iPad touch version of UMK3, but in a different way. Instead of holding down on the buttons during the loading screen (since that is impossible), one has to press on cyborg Smoke and hold onto him for a few moments. After a while, Cyborg Smoke will be replaced with Human Smoke.
- Classic Sub-Zero: The speculated original form of the elder Sub-Zero before his death at the hands of Scorpion. Possesses the same moveset as the younger brother from the 2nd game, having only the Ice Blast, Slide attack and Ice Puddle. He can be both fought at the end of the game via Shao Kahn's Treasures and unlocked using the Ultimate Kombat Kode 81835-81835.
- In the iOS version, Classic Sub-Zero is unlocked from the start.
- Mileena: Reappearing now as a secret character in the game, complete with her own original set of moves from the second game. Same situations for Classic Sub-Zero applied to Mileena. UKK is 22264-22264.
- In the iOS version, Mileena is unlocked from the start.
- Ermac: Once rumored to be a secret character in the first game due to a bug. Ermac makes his first official appearance in the game as a tanned, red palette-swapped version of Scorpion with his own set of moves, possessing the power of telekinesis. Same situations for Classic Sub-Zero and Mileena apply to Ermac. UKK is 12344-44321.
- In the iOS version, to unlock Ermac the player needs to beat Arcade Mode on Warrior or above difficulty and then pick the treasure that has the Ying Yang symbol.
- Noob Saibot: Same as his MK3 appearance, but with the appearance of a ninja instead of Kano. In the arcade version, he still technically possesses Kano's combos, but they have been translated into the ninja's sprite sheet. In the SNES and Genesis/Mega Drive versions, he is a playable character from the start, having access to new combos as well as his own special moves: a disabling projectile, a teleporting slam and a shadow throw attack.
- Rain: Not exactly a secret character, but a "joke" who appears in the arcade version's attract mode. No coding for him actually exists in the game, but in the SNES and Genesis versions he is a playable character from the outset. His stance is a palette swapped version of Reptile's. He utilizes weather related powers, calling a thunderbolt from the sky to strike the opponent from above and a body controlling water ball projectile, as well as the infamous "super roundhouse".
- Chameleon: An odd palette swap of sorts. Chameleon appears as a partially invisible ninja whose color randomly switches to the colors of the male ninjas which corresponds to which moves he will copy. He can be both fought via Shao Kahn's Treasures and accessed as a playable character via the same code as Human Smoke, which is holding Back, High Punch, High Kick, Run and Block, while playing as any male ninja before the start of the round. (Only on PlayStation).
- Khameleon: A partially invisible, white palette swapped version of all of the female ninjas that unlike Chameleon, tends to fade in and out of vision, whereas Chameleon is simply transparent. Also unlike her male counterpart, Khameleon's colors do not change, but rather, her name in her health bar does. Depending on the color, Khameleon's moveset will change to the corresponding female ninja at random intervals, making her hard to play. She can be fought through one of two ways: at the Star Bridge, one of the players must press Down and Start when Dan Forden pops up. A confirmation identical to the MKII hidden character battles will pop up. Or the player can access the Secret Endurance ladders where Khameleon is located on the Champion ladder at the very bottom. Regardless of the method, she will always be fought at the Hidden Forest. She can also be unlocked one of three ways: either through the Blue Question Mark option (unlocked through a cheat code), or through the Ultimate Kombat Kode (113-840), which also unlocks Human Smoke. She is only available in the Nintendo 64 version.
- Human Smoke: Reappears the same as before, but with new Fatalities. As with Khameleon, the same situations apply to him. Unlockable in the N64 version but initially playable in all other versions.
- Meat: Initially appearing as a model glitch, Meat serves as the model used for characters who are skinned alive from Fatalities, resulting in a bloody skeleton covered in mangled and severely mutilated flesh. His moveset depends on the character who was initially chosen when the conditions for playing as him are met. To play as him, one must go to Vs. Mode and select the "Group" option in the Character Select screen. A small box will appear, showing all of the characters in the screen, and the player will start playing as all of the characters from left to right (beginning with Kai and ending with Sonya). As the battles are won, the last character who was played and the next character that will be played as at the time of victory will be blanked out in red. Repeating for the entire roster and then selecting any character lets assume the role of Meat. In the arcade version of the game, clearing the game with Meat will cause the game to crash.
- Reptile: Reptile appears once more as a secret character, but only in the Game Boy Color port of the game. As with Smoke in MK3, he is only selectable when the portrait rotates to reveal his face. Accessible with the Kombat Kode 192-234.
- Noob Saibot: Returning once more from Mortal Kombat 3, here he appears as the original model for Reiko with his moves included, he wields a scythe as weapon. Originally slated to be part of the outset of playable characters in the arcade version, he was removed to make way for whole new characters, but became an unlockable character in the console ports. There is a code known as Noob Saibot Mode which enables him as selectable without prior requirements. Alternatively, the player must clear the game with Reiko and the select the Hidden option and highlight him (press Up, Up then Left for reference when starting from the Hidden option) then press Run+Block. He has Fatalities, but they can only be executed with the Easy Fatality codes.
- Sektor: Returning from Mortal Kombat 3 as one of the three hidden playable characters. He appears as a texture-swapped version of Cyrax retaining his original moves. To play as him, one must choose the Hidden Option and move the hidden cursor one space left of Cyrax.
- Noob Saibot: Reappears the same as before, but now in fully playable form. However, his Fatalities are still inaccessible through normal play. Same situations for Sektor apply to Noob Saibot but replace Cyrax with Reiko.
- Goro: Highlight "HIDDEN" at the bottom of the character selection screen & press "L" trigger & "R" trigger. Continue to hold these buttons and then press Up, left, A.
- Mokap: One of the two hidden characters who can be unlocked in the game. Mokap is the alternate, in-game identity of motion capture actor, Carlos Pesina, who provides all of the motions for every character in the game. He uses moves and styles borrowed from other characters, lacking a weapon style. He is unlocked after completing the Konquest mode with all characters, including the unlockable ones. To select him, one must highlight Cyrax and then hold down and press Start. If successful, the announcer will call Mokap's name instead of Cyrax. Because only one player is allowed to choose this character, he does not have an alternate attire.
- Blaze: First appearing in MKII as a minor background character. Blaze is a fire elemental, cursed with the task of forcefully guarding the Dragon Egg of the Dragon King. As with Mokap, he uses moves borrowed from other characters and lacks a weapon style. Unlocked the same way as Mokap. To select him, the player must highlight Raiden and then hold down and press Start much like with Mokap. If successful, the announcer will call Blaze's name instead of Raiden. Having the same limitations as Mokap, he can only be chosen by one player and does not have an alternate attire.
- Kano, Kitana and Sub-Zero are hidden characters in the Game Boy Advance version. However, they can also be fought if they aren't unlocked depending on difficulty.
- Liu Kang: His status as a secret character qualifies, as Midway was very secretive about his appearance in the game, careful enough so that no information regarding him would be leaked, as well as the conditions needed to locate his key. He appears in an undead form, his body reanimated by the now dark Raiden to carry out his will. He possesses all of his moves from Mortal Kombat 4, but is unusually strong compared to the other characters. While his spirit can be fought at Earthrealm, his unlock key must be found at Edenia at a very specific time and location.
- Ermac: As a tribute to the oldest rumor in the book, Ermac appears as a secret character, his design based on his Deception appearance. He is located in the Warrior Shrine at the Wu Shi Academy, which is based on one of the supposed methods to reach him in the first Mortal Kombat. In order to reach the Warrior Shrine, players must "make an offering" to the statue at the right, which can only be reached with the Pole Swing ability. Doing so unlocks the gate to the Warrior Shrine. Inspecting the mysterious appearance of his statue amongst the collection in the shrine from the first game three times will cause Ermac to emerge from his rocky cocoon to automatically do battle. He is especially hard, using telekinetic powers with a sizable range and the ability to teleport.
- Kano: He is found right before entering Shao Kahn's arena. To fight him, players must talk to Kitana until two masked guards appear. After defeating them, just head to the dungeon to fight the Black Dragon mercenary with the help of Jax.
- Mileena: She is found in the Living Forest. To reach her, double jump to reach the branch right in the beginning of the level, then swing to the ladder. Search the area above for a large hollowed-out tree.
In a tribute to MK's history, secret characters make their return for this installment as the original incarnations as they first appeared. Although limited in movesets and lacking Super Meters, they have greater stamina, speed and sometimes, special abilities.
- Klassic Noob Saibot - He is found in The Cathedral. If he is seen standing in the background of the stage, simply win the match without blocking. Noob Saibot will be there at the start of the round or not. Noob Saibot will then proceed to fight with the player, appearing much stronger than the other ninjas.
- He only has access to the Teleport Slam, which he will repeatedly spam, which allows prepared players to quickly defeat him by simply blocking his attempts and countering with an uppercut or X-Ray Move, but is unusually strong. Because the Compatibility Packs came after the release of the game, Klassic Noob Saibot uses a completely black version of the MK uniform. By losing, the player will receive 25 koins in each round.
- Klassic Reptile - He is found in The Pit Stage. Very similar to the original MK requirements, a shadow figure must go across the screen, and the player must win with two flawless victories in a row, and with a stage fatality. A loading screen will then appear, and the player will be transported to the Pit Bottom to fight Klassic Reptile.
- Much like the original Reptile that debuted in the first game, he is twice as fast and possesses Scorpion's Spear and Sub-Zero's Ice Blast, with the added ability to turn invisible. The player will receive 5000 Koins for every round won.
- Klassic Smoke - He is found in Living Forest. Like the other two, this character pays a homage to the original secret characters, but unlike the other two, once Down + Select (Playstation 3) or Down + Back Button (Xbox 360) are pressed when he appears from behind a tree, the opponent will be taken out and he will fight the player himself.
- Much like his MKII incarnation, Smoke has incredible speed and uses Scorpion's Spear as a special move. Because the Compatibility Packs came after the release of the game, Smoke uses a gray swap of the MK uniform. The player will receive 2,000 Koins for each round won.
- Klassic Jade - She is found in Goro's Lair. To fight her, the player must beat the Tournament Ladder, up to Shang Tsung, without losing a single match. Shang Tsung then must be defeated with two Flawless Victories and a Fatality. The player will then be transported to Goro's Lair and fight Klassic Jade there.
- Much like her MKII counterpart, she has access to Kitana's Fan Throw, as well as an absolute immunity to projectiles, and white skin. Because the Compatibility Packs came after the release of the game, Klassic Jade simply uses the MK3 uniform, and her fans are green instead of bronze.
In addition to secret characters, some fans had claimed that other characters existed in the first two games, whom could only be reached by even more challenging conditions to meet before fighting them.
- Ermac: Ermac was the source of much controversy within the fanbase. One gamer had reported a glitch in the color palette swaps that replaced Scorpion's yellow colors with red (the original color of the costumes used when capturing footage), in the form of a new character known as ErMAC, a shortened form of Error Macro. This report's validation was further supported by checking the arcade's menu. Under a list of stats, there was one named ERMACS; thus, people were led to believe that Ermac did indeed exist. However, Midway had officially denied any coding of the character. Before the announcement, a list of methods were released to find him, most of them extremely hard. In Mortal Kombat II, his existence was further denied in the form of a scrambled message after defeating Shao Kahn, which unscrambled says: "ERMAC DOES NOT EXIST". Jade would also sometimes appear saying "Ermac Who?". He was later made into playable form in UMK3 (see above), with his fabled MK incarnation being made available as DLC in Mortal Kombat (2011).
- Nimbus Terrafaux: An April Fools prank from Electronic Gaming Monthly for the original Mortal Kombat on Sega Genesis, no coding for him exists in the game. He was described as being an African American kickboxer. The character's surname, Terrafaux, outright denies its own existence in the game, as it is a combination of both the Latin word Terra ("Earth") and the French faux ("false"), meaning fake Earth.
- Skarlet: A rumored character in Mortal Kombat II, a supposedly red-clad palette swapped version of Kitana, nothing else was known about her or how to reach her. The glitch is just like the Error Macro one from the previous game. Being unnamed, she was often called Skarlet by the MK community. There is no proof of whether the glitch is real or not, though fans often speculated that Skarlet was made up. The rumor was further enhanced when a similar red ninja named Ruby made an appearance in Mortal Kombat: Defenders of the Realm. Skarlet later made her debut in Mortal Kombat (2011) as a playable character through DLC purchase, using a pair of ninja swords in battle along with four small kunais. She is a being comprised of (and strengthened) by blood and yet another creation of Shao Khan's. In the same vein as Ermac, her fabled MKII incarnation was made available as an exclusive Klassic Costume in Mortal Kombat (2011) for the Playstation Vita.
- Red Robin: A rumored character in Mortal Kombat II, a supposedly red-clad palette swapped version of Reptile, nothing else was known about him or how to reach him.
- Kano: Kano was also rumored to have appeared in Mortal Kombat II as a secret character, via Shang Tsung's Morphing ability. Even a statistic named "KANO TRANSFORMATIONS" was listed in the menu. However, this was purely a ruse in order to cash in more money made by Midway. Kano exists in the game along with Sonya, but only can be found in Shao Kahn's Arena, where they are bound by chains.
- Johnny Cage: Johnny Cage was also rumored to have appeared in Mortal Kombat 3 as a secret character, via Shang Tsung's Morphing ability. Even a statistic named "JOHNNY CAGE TRANSFORMATIONS".
- Pedro: A Stryker palette-swap, Pedro was rumored to be in Ultimate Mortal Kombat 3, and was said to be a Mexican fighter who would fart fire as an attack, but it was later proven to be an April Fool's Joke from video game magazines. Ironically, the "Fire Fart" idea would later be given to Bo' Rai Cho as a Fatality.
- Aqua: He was a Japanese costume-ninja in Mortal Kombat Trilogy, a supposedly yellow and black palette swapped version of MK1 Scorpion. Unlike the previously mentioned characters, one evidence of its existence is found within the game's sound files: a soundbyte from the announcer proclaiming "AQUA WINS".
- Belokk: Belokk was originally a removed character in Mortal Kombat Gold, but was said to be unlockable through Tanya's box, which did not unlock any characters. This was later revealed to be a glitch let out by the designers.
- In the original version, upon defeating Reptile, the player is awarded with 10,000,000 points. In the Sega Genesis version however, the player is awarded with 1,000,000 instead.
- Reptile does not exist in the handheld versions of the game (Game Gear and Game Boy).
- Reptile's name is displayed in his health bar in the SNES version as opposed to SCORPION.
Mortal Kombat II
- In the Sega Genesis version, all hidden characters are fought at a blue colored version of The Portal stage.
- Noob Saibot could only exist in the Game Boy version by linking up 2 Game Boys. He could be fought after 25 consecutive wins.
- Noob Saibot does not exist in the Game Gear version.
- In the Sega Genesis, Amiga, Sega Saturn and PlayStation versions, Jade is Caucasian instead of dark skinned.
- The Amiga version has a slightly green-tinted version of Goro's Lair.
- Additionally, Jade is fought normally in the tournament without any special requirements, eliminating her status as a secret character altogether.
- In all ports of the game, Jade's name is added to her lifebar, which was strangely absent in the original version.
- In the Sega Genesis version the easiest way to beat Smoke is: just as he launches the harpoon, attack with an air kick, Up + Right + PA (or PB).
Mortal Kombat 3
- Smoke unlocks differently in both versions.
Ultimate Mortal Kombat 3
- All secret characters with the exception of Human Smoke are initially playable from the start in the Super Nintendo and Sega Genesis/Megadrive ports of the game. Rain is now a playable character.
- Sheeva sort of qualifies in the SNES and Sega Genesis versions. Despite being excluded from the game, her coding still exists in the game, but she has no sprites of her own with unnaturally broken stats. She is accessible in the game's secret Tournament mode by using random select, represented as the E portrait used for Endurance matches.
- In the Sega Saturn version of the game, Noob Saibot is once more a palette swapped version of Kano.
- In the Game Boy Advance version, Mortal Kombat Advance, Human Smoke is an unlockable character. He is unlocked by beating the Warrior Ladder.
- The Sega Genesis version 'featured' Chameleon as an unfinished character only playable through a cheat device. He uses Scorpion's sprites but turns into Rain when a Fatality involving dismemberment is performed on him. He has no special moves or combos. His Vs. portrait is the ninja character's, albeit with a mismatched color palette.
- Playing as Human Smoke forces the background to Scislac Busorez and will remain so in all succeeding matches (except bosses) until the player loses and chooses someone else.
Mortal Kombat Trilogy
- The N64 version replaces Chameleon with his female counterpart, Khameleon. Human Smoke is also an unlockable character.
Mortal Kombat 4
- Meat does not exist in the Game Boy Color port.
- Reptile is unlockable in the same version however.
- Noob Saibot's name is not called out in the PSX version and the music continues even after he wins
- Noob Saibot's fireball produces a fiery effect in the N64 version but is identical otherwise to Tanya's in the PSX version.
- In the N64 and Dreamcast versions of the game, one of Noob Saibot's Fatalities is Sub-Zero's Deep Freeze, but in the PSX version, he retains Reiko's Shuriken Barrage.
Mortal Kombat Deadly Alliance/Tournament Edition
- Mokap and Blaze are not in the Gameboy Advance version of Deadly Alliance, nor in Tournament Edition (which is an update over the GBA version of Deadly Alliance, with characters that were left out on the other game).
- Reptile was created by mixing up the palettes together to create the concept. He literally serves as a fusion of the two playable ninjas.
- It is a very common misconception that Sonya and Scorpion cannot fight Reptile due to their Fatalities using the Block button. More commonly for Sonya as Scorpion's does not actually require use the Block button though most players hold it to prevent the character from jumping. The game will allow the battle to commence if the Fatality is executed however.
- Rain was named and colored after Prince's album Purple Rain. In both Deception and Armageddon, it is said that he is also a prince, completing the homage full circle.
- Khameleon was the very first secret character in the series to debut with her own cohesive backstory. In addition, her appearances are rather unique in that, so far, she only appears in the Nintendo ports of the games she appears in.
- In the Sega Genesis/Megadrive version of the first game, it was possible to fight glitchy versions of the normal characters during the Endurance Rounds. When fighting Reptile in one of these, the second opponent retains the powers of Reptile, with their color palettes using the same palette as said character. Since the color areas are different from non-ninja characters and because the characters use unique sprites, this causes the glitched characters to perform odd acts whilst using the Spear, Ice Blast, Slide and Fatalities.
- In addition, it is also possible to see the palette errors on all playable characters at the character select screen, which requires to press start on the vacant controller and simply highlight them.
- Unlike the other secret unplayable characters from MK up to UMK3, Noob Saibot in his UMK3 arcade incarnation was stable when made playable through character modifiers, having a defined moveset accessible through human input, leading to speculation that he may have been playable at one point, as indicated by the Wave Net version. This is supported due to the fact that secret and boss characters were made specifically for CPU input, and running them through a human button input would cause the game to crash due to undefined executions, as CPU opponents controlled characters differently.
- In MK 2011, using Shang Tsung's Soul Steal move on any of the three classic male ninjas will cause their outfits to turn black at some point during the match (the exception being Noob, whose skin changes color). The use of the move after their color change will result in them reverting back to their original color. They still fight normally when changed. This also happens when the move is performed on the ninjas while they wear a classic costume. It seems the glitch has been patched on update 1.07.
- Additionally, it's possible to play as the secret characters through the Soul Steal move, but doing so removes the player's Super Meter.