Mason decided to take Squirtle with him upon hearing Selena abandoned it after it lost against Clarissa's Charmander. At first Squirtle was afraid of humans due to Selena's anger but eventually opened up to Mason, Katrina, and Clarissa. He later evolved after encountering his old trainer. After evolving he was a lot more open to Pokemon, especially Charizard since it had a fear of him.
Wartortle remained on Mason's team like before as was used frequently. At the end of XYZ, Mason knew that there was still some Flare Grunts out on the loose. He decided that his family needed more protection and asked Wartortle to stay with them. The Water-Type accepted and stayed behind.
Years after the original series Wartortle is still in his second form.
Personality[]
Wartortle has a loyal attitude towards Mason and looks up to his Absol. Upon his debut it has a childish demeanor and was babied by Absol and Mason. After evolving he loathed being babied and became a strong battler. It later help Skitty feel comfortable around other Pokemon when she joined the group.
While Wartortle is shown to be one of Mason's strongest Pokémon (Absol being the strongest), he is one of the main battlers.