Ninetales first appeared as a Vulpix when Enta partook in the Multi Battle challenge of the Battle Frontier. Vulpix gets quickly defeated as its opponent had the type advantage against it. Vulpix ends up getting blamed for the loss which caused it to run away. Enta makes it up to Vulpix afterwards by training and mimicking its movements. This made Vulpix's tail split into six. Vulpix has a rematch in the Multi Battle challenge whereas it did better than last time with the help of its Ability when it took damage from a Fire-type attack.
During Enta's challenge in the Battle Pyramid, he works with Vulpix along with his other Pokémon to go to the top after Rald told him that he needed to become one with his Pokémon. In the challenge, Vulpix was assisted by Enta's other two Pokémon to take on a Machamp. Later, Vulpix goes up against Rald's Sceptile when both of them were down to one Pokémon. Vulpix gets badly hurt despite the type-advantage which prompts Enta to forfeit the match. Enta trains Vulpix along with Feebas for his upcoming challenges. Vulpix was sent out along with Feebas to battle Tucker. During the midst of the battle, it gets taken out by Tucker's Salamence and Swampert, leaving Feebas to finish them off. Vulpix battled Spenser's Lapras and wins.
Later, Vulpix was used to battle Lucy's Shuckle where it was not shown who won. Enta continues to train Vulpix after his battle with Lucy. Prior to Enta's final battle in the Battle Frontier, Rald has one last practice battle with Enta where he battles his Vulpix using his Sceptile after both sides were down to one Pokémon. Despite the type-advantage Vulpix had, it was no match for Sceptile as Sceptile manages to defeat Vulpix. Rald gives the Fire Stone to Enta and Enta uses it on Vulpix so he could get stronger. Vulpix's contact with the stone caused it to evolve into Ninetales. During his battle with Anabel, he sends out Ninetales against her Snorlax after it defeated Milotic. Due to the damage Snorlax sustained earlier, Ninetales was able to knock it out with Hyper Beam. Ninetales then battled with Entei. Ninetales used many strategies and combinations to confuse Entei. One of those was when it used Substitute and then Hyper Beam while Entei wasn't looking. Even though both sides fought hard, they managed to knock each other out. As it was both sides' last Pokémon, the battle was a draw.