It is also the first Unova starter in Ash's team that evolved.
Before the events of The Battle Club and Tepig's Choice!, in the Accumula Town Battle Club, Tepig was sent out to battle against a Deerling under the ownership of his trainer Shamus. But somehow Tepig was badly beaten and lost the battle. After the battle, Shamus now realizes that his Tepig wasn't suited for battle at all when he's all that weak as he attempts to set him free, but Tepig still needs him here when Shamus made the decision to tie him to a post, abandon him, and left town. Don George wanted to untie Tepig but he chewed himself loose and ran away before Don George tried to get to him. When Ash visited the Accumula Town Battle Club, he initially mistook Tepig for an Umbreon after seeing it on a security camera stealing food from a warehouse. Ash discovered Tepig eating the bait he and Iris laid out for him and realized that it was actually a Tepig covered in soot. Tepig was extremely hungry and thin, as there was rope tied around his snout, preventing him from eating. Ash untied him, clean him and carried him back to the Battle Club. When Pikachu was stolen by Team Rocket, Tepig used Ember to rescue him. Ash then proceeded to catch Tepig.
Since Ash promised to use him in his first Gym Battle, Tepig fought against Chili's Pansear in Triple Leaders, Triple Threats!. His attacks did not do much damage to Pansear, whose Fire Punch, Flamethrower and Dig attacks hit Tepig hard. One of these Digs launched Tepig into the air. Ash commanded it to dive down Pansear's hole. Tepig then managed to bite Pansears tail and send it flying. He then defeated Pansear with a combination of Ember and Heat Crash.
He battled Lenora's Lillipup in The Battle According to Lenora and was forced back into his Poké Ball by Lillipup's Roar. After Lenora's Watchog defeated Oshawott, Tepig battled Lillipup again, but lost. After training in Rematch at the Nacrene Gym!, he battled Lenora's Herdier. After a short battle, he was sent back by Roar. After Oshawott and Watchog knocked each other out, Tepig battled Herdier again and won using its newly-learned Flame Charge attack.
He battled alongside Cilan's Pansage in Lost at the Stamp Rally! where they were battling against Subway Masters Emmet and Ingo's Chandelure and Eelektross while in the Battle Subway. It is unknown if they won or lost.
In A Maractus Musical!, he teamed up with Pikachu and Snivy to battle Toby's Maractus trio. Using their combination of Thunderbolt, Leaf Storm, and Flamethrower, they fought well. When one of the Maractus, Tussy, panics, they manage to win.
In Scraggy and the Demanding Gothita!, he was used to battle against Katharine's Mandibuzz. It used its full attacks against the -type Pokemon and fought well, dodging attacks. When their Brave Bird and Flame Charges collided, he remained victorious.
It evolved in Evolution by Fire! and turned the tide in the battle against his former trainer as he defeats his Fire Warriors: Emboar and Heatmor with its newly learned Fire Pledge and finishing off with Flame Charge. Seeing that he never liked it when Shamus said he could come back with him, it stayed with Ash instead, because he's now one of the gang since he evolved, that strengthens the connection of Trainers and Pokemons even more by the confidence of a dedicated trainer like Ash.
In Caution: Icy Battle Conditions! Pignite was used against Brycen's Cryogonal and Beartic He was able to take out Cryogonal by using Fire Pledge to aim for the center of the Rapid Spin but lost to Beartic when it used Aerial Ace for its Fighting-type weakness.
In Rocking the Virbank Gym! (Part 2), Pignite was up against Roxie's Scolipede and after his Flame Charge was blocked by Scolipede's Screech and it's Sludge Bomb was intercepted by Pignite's Flamethrower, Pignite used the smoke to his advantage and hit Scolipede with Flame Charge and after Scolipede dodged Pignite's second Flamethrower, it used Toxic and Pignite got poisoned but he managed to hang in there and defeated Scolipede with Fire Pledge. He was cured of the poisoning by the Pecha Berry that Roxie gave him. He continued to battle against Roxie's last Pokémon, Garbodor and after a tough battle, Pignite got knocked out by Garbodor's Hyper Beam.
Pignite battled Dawn's Mamoswine in BW090. It started the battle with a Tackle, dealing a decent amount of damage on Mamoswine. Mamoswine then hit Pignite with Take Down. Pignite managed to dodge Mamoswine's Hidden Power by quickly jumping and then hitting Mamoswine with a very powerful Flame Charge. It managed to counter Mamoswine's Ice Shard with Flamethrower and Mamoswine used Take Down and followed by Hidden Power. Pignite used Flame Charge and hit the Hidden Power head on, knocking both out and ending the battle with a draw.
|Ember||The Battle Club and Tepig's Choice!|
|Tackle +||Triple Leaders, Team Threats|
|Flame Charge +||Rematch at the Nacrene Gym|
|Flamethrower +||Battle for the Underground!|
|Fire Pledge +||Evolution by Fire!|
|+ indicates this Pokémon used this move recently.*|
- indicates this Pokémon normally can't use this move.
- Ash describes Tepig as being tenacious, though it lacks confidence when it loses.
- Pignite is Ash's fourth Fire-Type Starter Pokemon and the third to be abandoned by its original trainer.
- Pignite was revealed to have learned Brick Break in BW107 in Ash's battle with Cameron in the Unova League, 30 episodes after its evolution to a duel Fire and Fighting type pokemon.
- Ash's Pignite took the place of Bianca's Pignite since it evolved into Emboar prior in BW073: Searching for the Clubultimate! in the final match of round 1 of the Clubsplosion Tournament against Trip's Conkeldurr.
- Pignite as been used in 5 Gyms, the most from any of Ash's Unova Pokemon.