Duplica

Duplica is a ditto trainer and impersonator who first appears in episode 37: Ditto's Mysterious Mansion.

Background
While Ash, Misty and Brock traveled on their way to the next gym, it started raining heavily. To escape the rain, they ran into what they thought to be an abandoned house. While taking cover there, they see a pikachu with a strange face. Ash was determined to catch this new pikachu and tried to throw a pokeball at it, but the pokeball bounced back when someone hit the pokeball with their own pokeball. Then, a girl walked out from the shadows, dressed exactly like Ash. She explains to them that they are in the House of Imite, where she and her ditto put on shows by dressing up as other pokemon. The "pikachu" then transformed back into a ditto, showing it's true form. After Ash learned that ditto could only learn one move, he called it boring, which angered Duplica and caused her to challenge Ash to a pokemon battle. He accepted and chose bulbasaur as his pokemon, whereas Duplica chose her ditto. Ditto transformed into bulbasaur and grabbed bulbasaur with a vine whip, causing it to be useless, therefore, Ash had to give up. As Ash was depressed over his loss and wondering how the original could've lost, Duplica escorted everyone to the dress-up room where she entertained them by dressing up as Nuse Joy, Officer Jenny, and Misty. After having fun in dress-up room, Duplica explains to everyone that she wants to become a ditto master, but it seems impossible because her ditto can't seem to pull off imitating another pokemon's face, therefore, it keeps it's plain, small black eyes and wide mouth. She even had a flashback to when she was trying to perform to a crowd, but when ditto couldn't pull off a transform move, everyone booed and left. From then on, she had continued to train her ditto so it could transform completely.

Suddenly, after this, the lights go out and a spotlight shows on Jessie, James, and Meowth. They successfully grab Ditto and escape. Duplica, Ash, Brock, and Misty all chase after them and eventually find them. They perform their entrance by imitating the Team Rocket catchphrase while cosplaying as Jessie and James. This angers Jessie and James and James even yells at them for getting one of the lines wrong because they said to "to ignite all people within our nation" instead of "to unite all people within our nation." The kids are distracted for a moment and giggling about how fun doing the catchphrase was, but quickly turned their attention back to Team Rocket. They ask for ditto back, but cannot tell the difference between ditto and Meowth because ditto finally learned how to transform perfectly. Team Rocket takes this chance and purposfully gives Duplica Meowth instead of ditto. Duplica then ran after them and screamed that they still had her ditto, showing that she could tell the difference between them. She throws Meowth at the balloon and he crashed into Jessie, which causes her to let go of ditto and have ditto fly back down to Duplica. Pikachu then uses thunderbolt on the balloon and causes Team Rocket to "blast off again." Ditto then transformed into Pikachu and Ash became confused and said he couldn't tell them apart. Duplica then picked up her ditto and it transformed back, Duplica explained that she could always tell which one was her ditto. She later thanked Team Rocket form helping her ditto learn how to transform completely, even though they scared it to do so.

Ash, Misty, and Brock then bid farewell to Duplica since it had stopped raining and wished her luck at becoming a ditto master.

Ditto
Ditto is Duplica's one and only pokemon and it's her trusted partner. They perform cosplay shows together, and now that ditto can transform perfectly, their buisness went up. However, they did have a rocky start whenever ditto could not transform, but even though ditto couldn't transform all the way, Duplica still loved it and thought of it as a perfectly good pokemon.

Duplica is able to tell her ditto from any other pokemon it transforms into because she is so close to it.

Duplica's ditto, like all dittos, only knows one move, and that is transform. However, even though it only knows one move, Duplica's ditto is very powerful and easily defeated Ash in a pokemon battle with it.

Appearance
Although Duplica cosplays often, her main outfit is a red shirt with a yellow star on it and a pair of blue jeans. She keeps her blue-ish green hair in two pigtails. She is able to change her hair and voice at any time to imitate someone. She has also been in the imitating buisness for so long that she is able to change in a flash. This was proven when she was in the dress-up room with everyone and she was able to change just by running behind a shelf of clothes. She was able to cosplay as three different girls in under ten seconds.

When Duplica cosplayed as Ash, she copied everything about him perfectly, even the way he throws his pokeballs. This may reveal that she can pick up on every quality of a person in just a matter of seconds, especially since in the first five minutes that Ash was in the House of Imite, Duplica had already managed to make a perfect cosplay of him, and she could already imitate the way he talked.

Trivia

 * Duplica's name is a parody of the word "Duplicate" which means "the same as something else."
 * Although Duplica cosplays as other people's outfits, hairstyles, voices, and personalities frequently, she never puts on a wig to complete the cosplay. This may be a connection to the fact that her ditto could never finish a cosplay either because he couldn't transform his face.
 * Duplica had to shut down the House of Imite when the crowd hated the fact that ditto couldn't transform all the way, which is why it looked abandoned when Ash and his friends found it.
 * The House of Imite is a parody on the word "imitate" which means "to act like someone or something else."
 * Duplica made her second (and final) appearance in Pokemon Johto Journeys when she put on a performance in the pokemon center.