Chatler has been with Pearl since before the start of the series. Chatler first appeared in Stagestruck Starly, performing in Diamond and Pearl's comedy routine in Jubilife City. During the skit, Pearl has Chatler blow the grass away, however, when Chatler did so, it revealed Diamond and Lax's lazy selves, which made both Pearl and Chatler mad. Despite ruining the act, the audience found it funny, allowing Diamond and Pearl to win the special prize. Later the two are attacked by a group of Starly and Lax helps fend them off alongside the other Pokémon.
In Magnificent Meditite & Really Riolu II, Chatler participated in Platinum's Gym battle against Maylene. He was first used to fight against a Black Belt's Machoke with Aerial Ace. During the Gym Battle against Maylene, Chatler replaced Chimler when Chimler was struggling against Riolu. Chatler attacked with a super-effective Chatter and Maylene switched Riolu in for Meditite. Meditite started off a speedy Bullet Punch and followed up with a critical hit from Psycho Cut, dealing major damage. Despite the damage Chatler retaliated with Mirror Move and was able to beat Meditite by copying Bullet Punch. He then went up against Riolu again and was defeated by a single Vacuum Wave.
In Problematic Probopass & Mad Magnezone II, Chatler fought Cyrus after Cyrus had Magnezone use its magnetic powers to draw out the camera hidden inside Lax's fur. Chatler quickly flew by and grabbed the camera but was subdued by Probopass's Gravity. Chatler's Trainer, unable to do a thing in said state, asks for Cyrus to lift the attack. This allowed for Chatler to gain his mobility and crush the camera Cyrus used to capture the images of the ruin paintings.
In Winning Over Wingull, Chatler sensed two violent Wingull approaching and warned Pearl about the danger. Despite the warning the two Wingull hit Pearl and cause him to lose his balance. Angered, Pearl has Chatler attack the two with Pluck. Despite the speed advantage Chatler is quickly put at a disadvantage due to fighting two of them and their constant use of Roost. Because of this Pearl sends Chimler in to battle as well until he notices an injured Wingull near him.
In Chancing Upon Chingling, Chatler is sent to look for Diamond inside the Galactic Veilstone Building in order to return his Tru and Kit. Soon after finding Diamond they are attacked by the Advanced level Grunt and Diamond has Chatler attack his Chingling with Chatter while it attacked with Uproar in order to mask the sound of the Pokédex. After some time the two Pokémon become exhausted.
In Double Trouble with Dialga and Palkia VI, Chatler was used alongside the other Pokémon to battle against the Legendary Pokémon Dialga and Palkia. Despite his small size, Chatler was able to do great damage to the Dragons with the help of Diamond and Pearl's Pokémon and with a combined technique, they were all able to destroy the Red Chains controlling them.
In The Final Dimensional Duel XI, Chatler is used to try and stop Charon from closing the portal to the Distortion World with his machine. Charon quickly uses the machine to control Chatler and have him attack his own Trainer instead. Rotom then shows up in a Proteam Omega toy and destroys the machine.
Personality and characteristics
Like his Trainer, Chatler is quick, impatient, and easily irritable, taking out most of his anger on Diamond's Lax, in a manner similar to how Pearl behaves towards Diamond. He is a fairly strong fighter and is occasionally used for battling, though Pearl tends to use Chimler over him. Pearl occasionally uses him to listen in on conversations and repeat them.