- Mortal Kombat II: "Shang Tsung's personal protector, Reptile lurks in the shadows stopping all those who would do his master harm. His human form is believed to disguise a horrific reptilian creature whose race was thought extinct millions of years ago. He enters the contest hoping to defeat all and protect his master."
- Ultimate Mortal Kombat 3: "Always a reliable servant to Shao Kahn, Reptile is chosen to assist Jade in the capture of Kitana. In contrast to Jade's instructions Reptile is ordered to stop the renegade princess at all costs …even it means her death."
- Mortal Kombat 4: "A general in Shinnok's army of darkness. Reptile once belonged to an extinct race of reptilian creatures. He was banished to the Netherrealm for committing genocide against several species. Responsible for the death of millions, Reptile is a dangerous ally to the forces of evil."
- Deadly Alliance: "Reptile had discovered the plot devised by Shang Tsung and Quan Chi to assassinate Shao Kahn. But on his way to inform his master, he was distracted by a vampire woman named Nitara. She led him to the hidden base camp of Kitana's forces. Knowing the location of the base would be a great help to the Emperor in the war against Edenia and the Shokan. Eager to relay all that he had learned, Reptile raced back to Shao Kahn's Fortress, only to discover him lying dead on the throne room floor. Reptile's detour to Kitana's base camp had delayed him just long enough for Shang Tsung and Quan Chi to spring their attack on Shao Kahn. Reptile was devastated that he had failed his master and wandered the Outworld wastelands aimlessly until he once again crossed paths with Nitara. Desperately in need of a master, he offered his loyalty to her. Her first command to him was to attack the invader from Earthrealm, Cyrax. She explained that he must first destroy his arm panel in order to weaken the outsider."
- Bio Kard: "The warrior known as Reptile had served Shao Kahn not knowing that the Emperor had destroyed his home realm of Zaterra. Many years later, Reptile's body was possessed by the soul of the Dragon King and was transformed to resemble the former ruler of Outworld."
Reptile faithfully served as Shang Tsung's protector in the first tournament. Being a master of stealth, he stayed hidden and constantly watched over Shang Tsung, staying true to his duty. He rarely fought, but was a very skilled fighter. He utilized many special abilities, which added to his fighting skills to make him a force to be reckoned with.
He protected his master from harm, and then went on to receive special missions from Shao Kahn himself, who had promised to release the remaining members of his race from slavery if he would unquestioningly do his bidding.
Such an opportunity arose when Kitana had escaped into the unknown regions of Earthrealm during Kahn's invasion of that world. Reptile was sent by Shao Kahn, who promised Reptile to resurrect his race if he succeeded, with Jade to find and, if necessary, kill Kitana. He did not succeed as Jade betrayed him to help Kitana.
After the war was over, with Kahn defeated and both Earth and Edenia free, Reptile was brought back as a prisoner to Edenia, and tried there for genocide, a bitter irony since his own race once was the victim of the very same act. Reptile was then exiled to the Netherrealm.
When the fallen Elder God Shinnok invaded Edenia, Reptile grasped the opportunity to join Shinnok's Army of Darkness as a commander, hoping to convince Shinnok to revive his near extinct race. After being on the losing side once more, he escaped into Outworld again and rejoined his old masters, in spite of the fact that neither had ever kept their promises towards him.
Because of his state of separation from the other members of his race, and especially his matriarch, Reptile had begun to show signs of devolution. Where he used to mask his appearance by posing as a human, this proved to be no longer possible. Reptile had nearly gone insane and had a significantly changed in appearance, including bare feet and a tail.
With the armies of Edenia and Outworld locked in combat, Shao Kahn requested the services of the sorcerer Shang Tsung. Reptile was sent to tell Tsung of the emperor's request but upon reaching Shang Tsung’s new place of residence since being released from prison, Reptile overheard Tsung and Quan Chi forming their alliance and plotting to kill Shao Kahn. On his way back to inform his master, he was distracted by Nitara, who revealed to him knowledge of his lost civilization. She gave him the Kirehashi blade, which was an artifact of the Zaterran civilization, as proof and revealed to Reptile the location of Kitana’s forces. Reptile knowing how this knowledge would greatly aid his master in the war with Edenia raced back to tell the emperor, but he was too late; Shao Kahn lay slain on the floor.
The desperate and purposeless Reptile wandered Outworld aimlessly until he came across Nitara yet again. Desperate for a new master Reptile declared his loyalties to Nitara, but unknown to Reptile, he had always been merely a pawn in Nitara's plan to free her people's realm from the Outworld. The first step had been to distract Reptile long enough for the Deadly Alliance to kill Shao Kahn unhindered; next, she manipulated Reptile and the cyber-ninja Cyrax into battle. Reptile damaged Cyrax, ensuring the cyber-ninja would later help Nitara in her quest for the Portal Sphere. Eventually, Reptile came to realize that Nitara had fooled him, and that her plan had lead to the death of his master Shao Kahn. Enraged, Reptile tracked the vampire and Cyrax to the Lava Shrine, but he was too late. The portal sphere had been destroyed, and of Nitara and Cyrax there was no sign. All that remained was the almost fully incubated dragon egg of Onaga the Dragon King. The egg hatched, a beam of light struck Reptile and Reptile's body became the vessel for the reincarnated Onaga (It is unknown if the egg still became another dragon after that but it is unlikely).
It is described in an unlockable photo of Reptile's home realm Zaterra that members of his race can lose their humanoid appearance when separated for long periods of time from their monarchical leader; given the fact that this authority figure - like most of his people - were most likely wiped out centuries ago by Shao Kahn, the fact that Reptile did not start to 'devolve' until after he assumed his master was killed at the end of Mortal Kombat Trilogy, and his race's natural camouflage ability to look like normal humans, it's more likely that Reptile's 'devolution' was a result of his increasingly maddening state overriding what mental capacity was required to maintain his human guise instead of a physical metamorphosis into a prior state of evolution.
Reptile's separation from Onaga was seemingly explained by Nightwolf's ending in Deception, whereupon he bound Onaga's soul to the Netherrealm and Shujinko's opening in Armageddon, where his body is seen on the floor, lifeless after the final blow delivered by Shujinko. He is encountered by Taven in Konquest mode in the lair of the Red Dragon clan. Though no explanation is offered as to why he is there, it's possible that Reptile's DNA was also being used, along with Daegon's dragon, Caro's, as a means of creating human-reptilian hybrids, since the Red Dragon Hybrids do bear some resemblance to Reptile and can also spit acid. This might have been another way, in his eyes, to get his Saurian race to be restored. Taven defeated Reptile in a fight and released Caro.
Reptile later joins the Forces of Darkness and is killed during the final battle.
- Mortal Kombat II (Non-Canonical): "Reptile has always loyally served as Shang Tsung's protector - while maintaining a very low profile in the first tournament, he discovered Tsung's plot to force the remaining members of his near extinct race into slavery under Shao Kahn's rule. Reptile then devises a plan of his own. He enters the Outworld tournament, defeats Shao Kahn and turns against Shang Tsung, ending his master's scheme. Now his race can live on in their own peaceful existence."
- Ultimate Mortal Kombat 3 (Non-Canonical): "Reptile was ordered by Shao Kahn to find and kill Kitana. He is successful in completing his task, but upon returning, finds himself shunned by the emperor. Shao Kahn promised Reptile that if he was successful that he would resurrect Reptile's race. Shao Kahn never had any intention of keeping his promise. Enraged, Reptile turns against his master and defeats him in battle but by killing his master, Reptile destroys the one chance to ever know his true race."
- Mortal Kombat 4 (Non-Canonical):
- Reptile: (kneels before Quan Chi) Quan Chi... I have served the Lord Shinnok well in destruction of Earth's warriors.
Quan Chi: Yes. We are most appreciative of your efforts.
Reptile: Now I wish to return in time to my homeworld before it was destroyed by the hands of Shao Kahn. As the new ruler supreme of all of reality, Shinnok alone has the power to grant me this wish.
Quan Chi: You dare make such an impetuous request from your Lord and Master?
Reptile: It's a simple request for one of such great power.
Quan Chi: It's also not worth his attention.
Reptile: (stands up, enraged) I demand it! If it were not for warriors such as myself, his attack against Raiden's forces would have failed!
Quan Chi: Perhaps you can convey your feelings to Shinnok himself.
(Shinnok suddenly appears in front of Reptile and holds him in a choke hold)
Shinnok: Infidel! You are in no position to demand anything! I could kill you with a mere thought!
Reptile: (choking) ... But... We had a deal...
Shinnok: A deal? I am not a god of my word, Reptile. All deals are off! (Reptile's head explodes in Shinnok's hands)
- Deadly Alliance (Canonical): "Despite the strong sulfurous stench that filled the chamber, Reptile could smell that Nitara and Cyrax had been there recently. There was no sign of them now, except for some scattered glass shards and a residual trace of strong magical energies. His revenge would have to wait. Suddenly, an expectant hush filled the chamber as energy cascaded around what appeared to be a dragon embryo. The tiny dragon stretched and the egg cracked. A beam of energy ripped out from inside and lanced into Reptile. His world was filled with roaring power as his squamous body was twisted and transformed. The ancient prophecy had been fulfilled: the Dragon King had returned."
- Armageddon (Non-Canonical): "As the shock wave caused by Blaze's death rattled the surrounding crater, the pyramid on which Reptile stood began to crumble. A fissure opened to reveal a sarcophagus of familiar design. Reptile unlocked the curious artifact to find a female Zaterran. As she awoke, Reptile felt himself slowly reverting back to his humanoid form. The glory of Zaterra will return once more!"