Charmander and Professor Sycamore
Salamè was originally a first partner Pokémon owned by Professor Sycamore. Salamè debuted as a Charmander in They Have a Flare for a Li'l Kanga-Napping, standing besides Professor Sycamore and his Bulbasaur and Squirtle.
Prior to What Does Charmander Do When It Dozes, Charmander ran away from Sycamore's lab and took a nap in the flowerbeds on Route 4. As he slept, his tail accidentally came in contact with the flowers, setting them ablaze. As Charmander freaked out, the Froakie that was traveling with X's group put the fire out with his Frubbles. When Chespin and Froakie recognized Charmander, X's group realized he must belong to Professor Sycamore. They decided to take Charmander and return him to the professor, but he was taken by Sina and Dexio after they mistook X's group for thieves. Using his Roller Skates, Tierno took back Charmander and explained the situation to Sina and Dexio.
After returning Charmander Professor Sycamore questioned why X didn't let Chespin on his team. When X explained why, Professor Sycamore decided to have a battle and made X use Chespin while he used Charmander. X agreed but refused to actively take a part in the battle, forcing Chespin to fight by himself. With no Trainer and at a type-disadvantage, Chespin was dealt heavy blows but refused to give up. Chespin's determination managed to impress X enough to actually take a part in the battle and had him attack with Rollout. Despite the powerful attack, Chespin was defeated. After the battle, X decided to keep Chespin and named him Marisso, and also took Charmander, which he nicknamed Salamè.
In Pangoro Poses a Problem, Salamè teamed up with Kanga and Marisso to battle the Lumiose Press editor-in-chief to protect Alexa. While Kanga and Marisso battled Pangoro, Salamè began to fight one of the chief's Spewpa. Due to it using Rage Powder, he was unable to listen to X's commands when he told him to attack the Pangoro. He eventually defeated the Spewpa but was left exhausted, allowing Pangoro to grab him and Marisso with its paws. X then told Salamè to release his tail, which caused Pangoro's leaf to burn up. Without the leaf allowing it to sense what Kanga and Li'l Kanga were doing, the two quickly defeated it.
In Quilladin Stands, Salamè trained alongside Marisso under the tutelage of Gurkinn. Eventually, Salamè and Marisso evolved into a Charmeleon and Quilladin, respectively. Salamè was later used in X's attempt to break into Team Flare's hideout in Geosenge Town. While sneaking in, Salamè used Incinerate to defeat a Team Flare Grunt's Noibat. Once inside Salamè teamed up with Marisso to fight Lysandre's Pyroar and Mienfoo. After a quick fight, X recalled them both so he could battle with one of his Pokémon that could Mega Evolve.
Salamè hiding in his Poké Ball
Salamè and Blue's Charizard defeating Xerosic
In Malamar Traps, after X and his friends left to confront Team Flare at the Pokémon Village, X revealed that Salamè began refusing to leave his Poké Ball after seeing the rest of X's team have their Mega Stones react to the Anistar City sundial. X later realized that Salamè became depressed due to fear that he may not be able to handle the power of Mega Evolution when he evolved into a Charizard. After seeing Marisso risk himself to protect him from Xerosic's Malamar, Salamè regained his confidence and joined the battle. Although Xerosic was confident that Charizard did not have a Mega Evolution, Salamè revealed that he had been keeping a Charizardite X on his tail the entire time.
Despite this, Xerosic refused to give up and continues battling by sending out more Pokémon to fight. Blue joined in the fight to assist X, revealing that he is also a Mega Evolution Successor possessing a Key Stone in the process. After Salamè evolved into his final form, both X and Blue activated their Key Stones to Mega Evolve both of their Pokémon into Mega Charizard X for X and Mega Charizard Y for Blue. The combined might of both Mega-Evolved Pokémon proved to be more than enough to defeat Xerosic. Salamè later tried to help suppress Mewtwo's rage at the Pokémon Village alongside Charizard, Rhyperior, and Marisso. Despite their numbers, Mewtwo kept the advantage, easily knocking them away with Psywave.
In Xerneas Gives, X had his final battle against Lysandre and his Zygarde. X used the power of five Key Stones to simultaneously Mega Evolve his five capable Pokémon at once. With their combined strength, Salamè, Kanga, Li'l Kanga, Élec, Garma, and Rute fought against Zygarde in order to defeat it. The combined might of X's team successfully forced Zygarde to split apart into its Cells, which led to Lysandre's defeat.