Gwendolyn's Aggron

Gwendolyn's Aggron (Japanese: グエンドリンボスゴドラ Guendorin's Bossgodora) is the first Pokémon that Gwendolyn ever owned.

Background
Gwendolyn recieved Aggron as an from her father,, when she was little. He was present the day that Gwendolyn and Jethro were attacked by a, but was not used to help fend it off. Arn first appeared as one of the four Pokémon that Gwendolyn started her journey with.

Aron helped rescue 's from a water fountain. With his ability to chew through metal, Aron was able to eat enough of the fountain for Gwendolyn to rip it off and rescue the Castform. It was soon revealed that was the reason Castform was trapped, and Aron and Torchic were sent out to battle them. Both Aron and Torchic defeated Team Aqua's and, but took damage from their  Ability. Due to the injury, Aron was unable to take out 's, but Torchic was able to defeat it with help from Castform.

Aron was Gwendolyn's first choice against and her. After exchanging an attack, Gwendolyn declares that Nosepass is too strong and decides to switch, but is unable to. Roxanne points out that Nosepass has and switching Aron out is impossible. Nosepass then attacks with a barrage of and attempts to finish him with. Roxanne declares the match over, but Aron climbs out of the rubble and attacks. Due to Nosepass being unable to face a different direction than north, it loses its balance when it turns around, allowing Aron to beat it and give Gwendolyn the victory.

Gwendolyn trains Aron and Torchic at in order to prepare for her  against. After training for most of the day, the two evolve into and. Gwendolyn then goes to Brawly and begins their battle. During the battle, Lairon is sent out against his and immediately attacks with  and. Using its Jū fighting style, Makuhita easily defeats Lairon, and Gwendolyn recalls him just in time.

Lairon battled against in a flooded cable car. Matt sends his Sharpedo in to finish Gwendolyn off, and Lairon jumps in the way and uses, breaking Sharpedo's teeth. While distracted, Gwendolyn takes the teeth and pierces the glass, removing the water. With the water gone, Lairon smashes into them with and sends them flying.

Lairon, alongside Tropius and Donphan, were used in Gwendolyn's battle against and her,  and. Although Winona's Pokémon prove tough, Gwendolyn manages to defeat her, earning the.

Lairon, alongside Gwendolyn and Jethro's other Pokémon, battled against and. Lairon was seen being pushed back by Archie's 's. Soon afterwards, Lairon evolved into during Gwendolyn's training on.

Aggron and Blaziken were chosen by Gwendolyn during her second match of the preliminary rounds of the, which consisted of , where they squared off against 's and. Tropius starts off by flying up in the air and whips a. Blaziken's burns the attack. Tropius's seems futile against Blaziken's. Swalot hits Aggron with a and Tropius's  sends Blaziken flying, but Blaziken uses Flamethrower on Tropius. Tropius dodges the Flamethrower and Aggron dodges Swalot's. Swalot seems to be a tough opponent since most of the attacks slip or bounce off its body. This happens when Aggron launches a.

Tropius defends against Blaziken's and Aggron's combined attacks. Blaziken and Tropius both faint after their Flamethrower and attacks, respectively, collide. Gwendolyn and Dominick are both down to one Pokémon now. Aggron gets dazed after getting hit from Swalot's and is sent flying. Aggron is then hit by a Body Slam and is then struck down by a Shadow Ball. Aggron gets up and charges through a Shock Wave and grabs Swalot and through it. Seeing this as a good attack, Gwendolyn tells Aggron to release a in Swalot's mouth. The attack explodes and after the dust settles, Swalot faints. Gwendolyn wins and qualifies to the next round.

In the finals, Gwendolyn selects Aggron as her fifth Pokémon to battle against Lenny's. Aggron is eager to battle and closes in on Grovyle while using. While Aggron continues its barrage, Grovyle launches a attack. Aggron evades the attack and repeats Flash Cannon. Aggron launches forward for a Take Down attack, but Grovyle manages to recover and counterattack with a, knocking Aggron unconscious and unable to battle.

Personality and Characteristics
Aggron is a mischievous Pokémon and loves to play around, though he always listens to Gwendolyn's commands without question. Like Gwendolyn, he has a love for battling and is very strong. He cares greatly for his Trainer. In battle, Gwendolyn is used for his defensive capabilities and tough exterior.