Ash's Tepig was first seen by Don George at his Battle Club when it original trainer came to battle. Pokabu lost to a Shikijika during the battle and its trainer tied it to a pole and left it. The Pokabu ended up getting the string tied around its snout making it impossible for it to eat.

Ash Ketchum saw Pokabu on the security camera video and thought it was an Umbreon because it was all dirty. When Ash Ketchum finally spotted Pokabu, he cornered it in an alley and tried to be friendly with it. Ash Ketchum noticed the rope tied around its snout and loosened it. Pokabu then helped rescue Pikachu from Team Rocket.

Iris wanted to get Pokabu but it wanted to be caught by Ash Ketchum instead. Realizing that Pokabu wanted to travel with him, Ash Ketchum captured Pokabu just outside the Battle Club in Karakusa Town.

Gym Battle Against Burgh's Dwebble

Burgh's Dwebble was the first Pokémon that Burgh sent out to battle Ash Ketchum during his gym battle. Ash's Tepig was the first Pokémon that Ash Ketchum sent out to battle Burgh's Dwebble. Burgh's Dwebble is very fast and combined with Dig, it proved to be a powerful opponent for Ash's Tepig. Ash's Tepig wasn't able to break through Burgh's Dwebble's Protect with its Flame Charge and got knocked back. Burgh's Dwebble quickly knocked out Ash's Tepig with Rock Wrecker right after that.

Battle Against Trip's Vanillite

Ash's Tepig was sent out and Trip's Vanillite was sent out to battle it. Trip's Vanillite had a major disadvantage against a Fire type like Ash's Tepig but Trip had intentionally paired them up because he wanted to win against Ash Ketchum by using his nonsensical battling style. Trip's Vanillite proved to have high defense as it was able to endure a direct Ember attack. It then countered with while Ash's Tepig used Flame Charge but they both ended up knocking each other out leaving the battle at a draw.

Battle against Katharine's Mandibuzz

Katharine's Mandibuzz battled against Ash's Tepig because Katharine's Gothita liked Ash's Scraggy but Ash Ketchum was not willing to part with it. Katharine made a deal with Ash Ketchum that if she won in a battle against him, he would be forced to trade his Zuruggu. Katharine's Gothita chose Katharine's Mandibuzz to battle against Ash Ketchum, while Ash's Tepig was sent out to battle against it.

Ash's Tepig proved to be the stronger Pokémon as it was able to endure Katharine's Mandibuzz's Brave Bird after it hit it directly the first time but on the second attempt Ash's Tepig countered the Brave Bird attack with its Flame Charge and knocked it out to give Ash Ketchum the victory so he didn't have to trade his Zuruggu.

Original Trainer Shamus

Shamus is Ash's Tepig's original owner. Shamus realized most Pokémon give up if he acted like the farewell pained him too so he abandoned Tepig because he thought it was a weak Pokémon battle and pretended to suffer as well by having to give Tepig up. Shamus was actually relieved when he was finally rid of Tepig. Shamus had tied Tepig up but while Tepig was trying to go after him, the rope got wrapped around its mouth.

Battle against Shamus

While at the Astilbe Town Pokémon Center, Ash's Tepig noticed Shamus and came up to it. After talking with Ash Ketchum and his friends, Shamus realized that this was the Tepig he'd let go. Ash Ketchum wanted to prove to Shamus that Tepig was a strong Pokémon and they decided to have a battle with Ash's Tepig as the focus. During the battle, Ash's Tepig evolved into Ash's Pignite.