In An Egg Scramble!, Dawn battled Lyra in the Johto Festival and defeated her. As a prize, Dawn was given an Egg, which was soon taken by Team Rocket. While it was in Team Rocket's possession, it showed signs of hatching. When Dawn finally got it back, it hatched right in front of her eyes, revealing it to be a Cyndaquil.
In Gone With the Windworks!, Cyndaquil battled Ash's Grotle and proved to be a strong opponent even though it had just hatched.
In Dressed for Jess Success!, Cyndaquil showed its interest in Pokémon Contests after watching Dawn practice with her Mamoswine by trying to mimic it with the flames on its back. It was shocked and upset when Dawn told it that it could not compete in the Lilypad Contest with her.
In Bagged Then Tagged!, when Dawn and Ash had a Tag Battle against Lyra and Khoury inside the Lilypad Colosseum, Cyndaquil was paired with Ash's Monferno to battle Lyra's Chikorita and Khoury's Totodile. It was able to defeat Chikorita with a Flame Wheel combined with Monferno's Flamethrower.
In Double-Time Battle Training!, Cyndaquil was used in a Double Battle together with Dawn's Mamoswine. After using the "Flame Ice" combo, it failed to execute it all of the way and Zoey's Leafeon defeated it, along with Mamoswine with a Magical Leaf combined with Kirlia's Psychic.
In Playing the Performance Encore!, Cyndaquil was used in the two-on-two Contest Battles of the Daybreak Town Pokémon Contest alongside Mamoswine. Both of them managed to defeat Ursula's Plusle and Minun in the finals earning Dawn her fifth and final Ribbon.
Cyndaquil and Buneary in the Grand Festival
In Last Call — First Round!, Cyndaquil was used in the Performance Stage of the Sinnoh Grand Festival along with Buneary. Their performance started with Buneary using Ice Beam to create a large frozen path resembling a roller coaster. Cyndaquil proceeded with Flame Wheel, rolling over the path and melting a trench for Buneary to slide on. After that, Buneary charged an Ice Beam and Cyndaquil used Smokescreen in order to cloak themselves above a large frozen spike. When the smoke was blown away, Buneary was seen inside a Poké Ball made of ice with Cyndaquil standing on top, impressing the Contest Judges and securing Dawn a place among the Coordinators advancing to the Contest Battles.
In Coming Full-Festival Circle!, Cyndaquil went up against Jessilina's Seviper and Carnivine in the semifinals of the Grand Festival along with Buneary. Together they managed to defeat their opponents and advance Dawn to the final round.
In DPS01, Cyndaquil was used in a Double Battle alongside Piplup against Johanna's Glameow and Umbreon, but when Piplup and Cyndaquil unleashed their Whirlpool-Flame Wheel combination, the battle was stopped due to them fighting. Cyndaquil then helped Dawn rescue a Piplup and a Chimchar that had escaped from Professor Rowan's lab from a group of Ariados. It became injured when it took a Poison Sting meant for Shinko. It was able to overcome its injury by evolving into Quilava and was able to defeat the leader of the group, a Shiny Ariados, with its newly learned move, Eruption.
In Piplup, Pansage, and a Meeting of the Times!, after it was introduced to Ash, Iris, and Cilan's Pokémon, Quilava brushed up to Ash, as a means of both greeting him and revealing that it had evolved.
In Goodbye, Junior Cup - Hello Adventure!, Quilava was used to battle Ash's Pikachu. It first hit Pikachu with Swift before dodging his Quick Attack and stopping Electro Ball with its newly learned Flamethrower. Quilava then covered the field in Smokescreen before stopping Pikachu's Iron Tail and landing a direct hit with Flamethrower. After their Flame Wheel and Quick Attack clashed in midair, Cynthia stopped the match.
Quilava appeared in The Gates of Warp!.
Cyndaquil's rivalry with Piplup
Cyndaquil copying Mamoswine's Contest move
As a Cyndaquil, it developed a strong bond with Dawn from the moment it hatched from its Egg. Prior to entering its first Pokémon Contest, it grew interested in watching Dawn train her other Pokémon, often showing Dawn its own variations of the moves that she was practicing with them, and sulked when it was not chosen to compete.
Dawn's Piplup appears to be jealous over the attention that it gets, though this may be attributed to the fact that Cyndaquil wasn't very responsive to Piplup at first. Piplup often attacks it and it in turn fights back, causing frequent squabbles between the two. They seem to be trying to compete for superiority over the other. These fights have stopped ever since Cyndaquil evolved.
It has a tendency to flare up its back when it's happy or when it's showing affection, and Dawn usually ends up getting burned in the process.
