In a flashback in A Rival Battle for Club Champ, Cilan recalled that Snivy had evolved into Servine prior to Triple Leaders, Team Threats!, and revealed that he defeated Chili's Pansear in Trip's battle for the Trio Badge. Ash challenged Trip to another Pokémon battle in a Battle Club in A Rival Battle for Club Champ!. He first faced Pikachu again, meeting Pikachu's Iron Tail with Cut and landing a powerful hit with Leaf Tornado. He then managed to stop Pikachu's Volt Tackle and win the match with another Cut. Servine then battled Ash's Snivy, where he dominated the match by dodging her Vine Whip and Leaf Blade attacks before hitting Snivy with another Leaf Tornado. However, he was eventually hit by Snivy's Attract, becoming immobilized by infatuation. It was in this state that Servine was defeated by a frenzy of Snivy's attacks.
Servine appeared again in Ash and Trip's Third Battle! in Trip's three-on-three battle with Ash. He once again battled Ash's Snivy, starting the match with Leaf Tornado, which proved even to Snivy's Leaf Storm. He then went in for a Cut attack, but Snivy dodged and used Attract. However, Servine was able to defend against the move, this time, with Leaf Tornado. He then stopped Snivy's Leaf Blade and defeated her in a single hit with Cut.
As a Servine
In Jostling for the Junior Cup!, Servine was shown to have evolved into a Serperior and was used by Trip in the Pokémon World Tournament Junior Cup. In the first round, he went up against Burgundy's Darmanitan and managed to freeze it in place with a Leer. Then, he easily knocked it out with a powerful Solar Beam, giving Trip the win. Then in the next episode, Serperior battled Manning's Heatmor in the second round and won with the same combination. Serperior soon battled Cilan's Crustle in the semifinals, and though Leer proved useless, he hit his opponent with another powerful Solar Beam. After avoiding Crustle's X-Scissor and Rock Slide attacks, Serperior swiftly finished the battle with a brutal Frenzy Plant. During the final match in Ash, Iris and Trip: Then There Were Three!, Serperior battled Ash's Pignite, revealing his Dragon Tail attack while avoiding every one of his opponents attacks. He beat Pignite, as he beat Crustle, with a Solar Beam and a Frenzy Plant. As a prize for winning the tournament, Trip and Serperior were granted a battle with Unova champion Alder. Serperior's opponent was Bouffalant and he started the match by launching a Solar Beam attack. Serperior's opponent was revealed to have the Ability Sap Sipper in the episode after, thus taking no damage from the attack. Regardless, Serperior hit his opponent with a Dragon Tail and a Leer attack while Bouffalant just stood there. Serperior's second Dragon Tail sent Bouffalant flying across the field but it quickly recovered and hit Serperior with Head Charge, knocking him out. After his defeat, Serperior would then listen to Alder's advice alongside Trip, with the Champion noting Serperior's strong affection for his trainer while emphasizing the importance of trust.
In Curtain Up, Unova League!, Trip sent Serperior out during his Vertress Conference preliminary round battle against Ash and his Pikachu. Being very fast and agile, Serperior was easily able to dodge all of Pikachu's attack attempts and strike back with a powerful Dragon Tail. The battle continued in Mission: Defeat Your Rival!. After attacking with an Energy Ball and a barrage of Dragon Tail attacks, Serperior used Wrap, tying Pikachu into an extremely tight grip. Even Pikachu's Thunderbolt proved useless, as Serperior used his tail to conduct the electricity to the ground. Pikachu was struggling to breathe, and Trip told Serperior to slam Pikachu down in order to finish him. Ash, however, was able to come up with a trick, and had Pikachu free himself by using Iron Tail on the field. As Pikachu tried to use another Iron Tail on Serperior, Serperior countered it with a Dragon Tail, and was preparing for another strike, when Ash invented another attack plan, and had Pikachu use a combination of Electro Ball and Iron Tail, which collided with Serperior's Dragon Tail, resulting in a big explosion. After the smoke cleared, Pikachu was still standing, and Serperior quickly fell down, defeated, giving Ash his first victory over Trip and eliminating the latter from the tournament.
Personality and characteristics
Serperior and Trip
As a Snivy, he was quite confident and self-righteous, as seen in In The Shadow of Zekrom! when Trip chose him over the other starter Pokémon, and during the battle with Ash. He has retained this trait after evolving. Serperior's most notable trait as it further evolved is his overwhelming speed, having swept through the entire Junior Cup without being touched once. Also, Serperior has very little trouble dealing with opponents who have a type-advantage, a further testament to his strength.
True to his species norm, Serperior holds his head high pretentiously while fighting and tends to stay elegant at all times. He does not take most opponents seriously, unless said opponent is particularly powerful, as seen in Goodbye, Junior Cup - Hello Adventure! when he was up against Alder's Bouffalant, showing signs of shock when his Dragon Tail didn't phaze his opponent. More signs of his species norm were seen after Serperior was defeated when it was bowing his head to Alder when the Champion talked to him and stroked his chin.