Fennekin first appeared as one of the three starter Pokémon new trainers can choose from Professor Sycamore, and was chosen by Serena as her starter Pokémon. Later on at the end of the fourth episode, a wild Vespiquen attacked Serena and Fennekin, who mistook it for a person. But Fennekin protected its trainer by scaring it away with an Ember attack. After joining Ash, Clemont, and Bonnie on their journey, Fennekin was used in its first Pokémon battle to help Serena to save Ash, Pikachu, and the Rhyhorn from Team Rocket.
Fennekin later helped Serena prepare a video performance called PokéVision. But during the filming, Fennekin was taken away by Team Rocket and her trainer and her friends went off to find and save her. When they found her along with Pikachu and Dedenne, Fennekin was hesitant to walk across the mud puddle because of her fear of being untidy. However, when she saw how Serena bravely risking her life to save her, she found the courage to run across the puddle to reach her trainer. In the battle against Team Rocket, she learned Flamethrower and sent them blasting off. After Team Rocket blasted off, Fennekin and Serena managed to finish the video and broadcast it just in time.
Later, Fennekin and Serena both participated in the Poké Puff Contest and were competing against Miette and her Slurpuff. But the contest was interrupted when Team Rocket stole the ingredients. Serena, Fennekin and their friends went off to look for the ingredients until they were ambushed by a group of angry Swirlix. Fennekin tried to protect Serena ended up getting entangled in Swirlix's sticky thread, but was eventually rescued by Ash and his Pikachu. She then scared the Swirlix away with a Flamethrower. When the gang were fighting against Team Rocket, she combined her attacks with Slurpuff and Pikachu and sent them flying. With the ingredients retrieved and returned, she helped Serena in the final round of the contest, but lost against the Berry baker kids.
She was later used in Pokémon battle against Serena's rival Shauna and her Bulbasaur. Fennekin launched a strong Flamethrower but was countered with a close range Energy Ball. Astounded with Bulbasaur's power despite her a type advantage, Serena and Fennekin lost the battle due to the First-Touch rule.
Fennekin is a very friendly and kind-hearted Pokémon with a very bold heart. It tends to mimic Serena's actions as shown when it stretches like her at the same time. It detests getting dirty, and always takes great care to look its best at all times, and can get angry if it gets dirty. However, it overcomes its fear of untidiness in order to protect Serena, though it never loses its desire to be beautiful. Fennekin can sometimes be very temperamental with other trainers and their Pokemon, but it always obeys Serena, and is even quite affectionate towards her.
|Ember||A Shockingly Cheeky Friendship!|
|Hidden Power||A PokéVision of Things to Come!|
|Flamethrower||A PokéVision of Things to Come!|
|Scratch||A Battle by Any Other Name!*|
|+ indicates this Pokémon used this move recently.*|
- indicates this Pokémon normally can't use this move.