Charmander immediately became one of Ash's main Pokémon, being used in the very next episode as a torch to help Ash through the caves. Also, it joined with a group of other Charmander on the St. Anne in Battle Aboard the St. Anne to repel Team Rocket Grunts. In The Tower of Terror, Ash sent it out to lead the way through the haunted tower, but it was terrified of the Ghost-type and Ash recalled it after it became paralyzed by Haunter's Lick.
In Primeape Goes Bananas, Charmander battled a berserk Primeape. It finally subdued its opponent by using Rage and Flamethrower. Charmander made its Gym Battle debut in the next episode, where it defeated Erika's Weepinbell after burning Razor Leaf and then striking a powerful Skull Bash. However, the pure stench emitting from her Gloom caused Charmander to choke and faint.
In The Ninja Poké-Showdown, Charmander battled Koga's Venomoth briefly before their match was interrupted by Team Rocket. For the official Gym battle, Charmander went up against Koga's Golbat and defeated it with Ember and Fire Spin. Charmander's power continued to grow, easily defeating a Golem owned by a biker named Chopper, despite the type disadvantage in The Bike Bridge Gang. The flames from Charmander's attack were so powerful that Golem continued to burn and the heat went through the Poké Ball.
The rise in Charmander's battle experience reached its peak in March of the Exeggutor Squad, where it helped stopped a large number of rampaging Exeggutor. Subsequently, Charmander evolved intoCharmeleon. However, in The Problem with Paras, it was revealed that Charmeleon was no longer loyal to Ash, attacking a Paras when Ash was trying to deliberately lose in order to help Paras evolve.Cassandra's grandmother explained that Charmeleon's skill level had exceeded Ash's, and therefore it did not respect him. Ironically, a rampaging Charmeleon was stopped when Paras, desperately trying to avoid punishment, jabbed at it with a claw. After evolving into Parasect, it put Charmeleon to sleep with Spore and allowed Ash to recall it. Cassandra's grandmother warned Ash that he needed to learn to control Charmeleon.
Ash stopped using his disobedient Charmeleon, but tried again in Attack of the Prehistoric Pokémon to repel wild Fossil Pokémon, which it refused to do. When an Aerodactyl swooped past, knocking Charmeleon over, Charmeleon proudly fought back but was unable to do anything. It then jumped up and grabbed the escaping Aerodactyl's tail and followed it into the open air, but was shaken off. Upset, Charmeleon evolved into Charizard and flew after Aerodactyl to avenge its injured pride. It managed to catch Ash and put him on the ground, but unfortunately, retained its disobedience.
Charizard's disloyalty began to cause Ash some serious problems during his journey, losing a round with Blaine in Riddle Me This, as it simply loafed off and allowed Rhydon an easy win with Horn Drill. In the next episode, Charizard refused to help dam the volcano, but changed its mind after seeing Blaine's powerful Magmar contributing. After working together, the duo were left with a burning desire to test each other's strength. Blaine permitted a battle at the peak of the volcano, and the two seemed evenly matched. Magmar dropped Charizard into the lava, but Charizard regained the upper hand by dazing Magmar with an aerial Submission attack and then knocking it out with its powerful Seismic Toss.
The most costly incidence of Charizard's disloyalty was in the battle against Ritchie during the Indigo League in Friend and Foe Alike. Down to one Pokémon, Ash called Charizard into battle against Zippo, and surprisingly decided to battle and force Zippo to flee from a far superior Flamethrower, causing Ritchie to recall it and concede the round. However, when Sparky came out, Charizard condescendingly stomped the ground and flapped its wings against the little Pikachu before going to sleep, refusing to battle. Due to this, Ash lost the round and Ritchie advanced onto the next round.
- Out of all Pokémon in the anime, Charizard has used the most moves with its total of 17 (19 if the unused Mega Punch and Fly are included).
- During the dub of Tanks a Lot!, Brock referred to Charizard as a male when he said that the Pokémon could use his Flamethrower to destroy the Arbo-Tank, but this is not considered canon since the Japanese version has never established Charizard's gender. However, Charizard's relationship with Charlamay imply that it is male.
- Charizard was the first of Ash's starter Pokémon to evolve to its final stage.
- Charizard became the first Pokémon in the anime to defeat a Legendary Pokémon when it beat Noland's Articuno in a battle.
- Charizard is the only Pokémon Ash has had that refused to obey him after evolving. This behavior was also seen post-evolution in Dawn's Mamoswine andIris's Excadrill.
- Until the episode Charizard Chills, Charizard only seemed to obey Ash when fighting another Fire-type Pokémon. It was obedient when battling againstBlaine's Magmar, Mewtwo's cloned Charizard, and Zippo.
- The Diamond & Pearl series is the only series so far in which Charizard did not make an appearance.
- It has become a running gag in the anime that whenever Charizard returns to Ash, it greets him by scorching him with its Flamethrower.