Tepig being abandoned by his previous Trainer
Tepig once belonged to another Trainer who abandoned him after he lost to a Deerling in battle. Tepig was tied to a post. When Don George tried to untie him, Tepig broke free of his bonds and began searching for his trainer. When Ash visited the Accumula Pokémon Battle Club in The Battle Club and Tepig's Choice!, Ash mistook Tepig for an Umbreon when watching a security tape of him stealing food from the nearby warehouse. In an attempt to capture the 'Umbreon', Ash then met Tepig for the first time when it was trying to eat some bait. He realized that Tepig was covered in soot and was unable to eat as there was a rope tied around his mouth, making him extremely hungry. Initially, Tepig tried to run away, but after being cornered by Ash and having its rope removed, he was carried back to the Battle Club by Ash.
Later on, Tepig volunteered to help Ash retrieve his Pikachu from Team Rocket. Later, when Iris wanted to capture Tepig, it refused and decided it wanted to join Ash's team, and Ash caught him in a Poké Ball.
Tepig fought for Ash during his Striaton Gym battle in Triple Leaders, Team Threats!, against Chili and his Pansear. Tepig's attacks didn't do much damage to Pansear, but Pansear managed to hit Tepig with Fire Punch, Flamethrower and Dig. One of Pansear's Dig attack sent Tepig into the air. Ash then commanded him to dive into the hole that Pansear was in and he managed to bite Pansear's tail. Although Pansear threw Tepig onto the ground, he managed to get up and spun Pansear around, throwing him to the ground. He used Ember successfully, and then knocked Pansear out with a powerful Tackle.
Tepig was revealed to be male in Snivy Plays Hard to Catch! when he battled a wild Snivy that would eventually be caught by Ash. Although he managed to use an Ember attack, he was hit by the Snivy's Attract and became infatuated with her, causing him to be recalled.
In A Rival Battle for Club Champ!, he was used to fight against Trip's Tranquill. Like Oshawott before him, he was defeated by two consecutive Aerial Aces due to Tranquill's Super Luck ability.
In BW015, he battled Lenora's Lillipup, which promptly used Roar to force Tepig back into his Poké Ball. After Lenora's Watchog defeated Oshawott, it fought Lillipup again and was defeated. In BW016, he battled against Lenora's newly-evolved Herdier, which soon used Roar to force Tepig back into his Poké Ball again. After Watchog and Oshawott knocked each other out, Tepig battled Herdier again and won using its newly-learned Flame Charge.
He had his third gym battle agaist the Template:Type2 gym leader Burgh in BW025, despite Ash planning to win with a type advantage, Burgh sent out a Dwebble which won with its own type advantage, giving Tepig little chance to do anything.
