Cynthia/Anime/Main/History/DP

Cynthia was first mentioned in Lucian's flashback in An Elite Meet and Greet!, along with the members of the Sinnoh Elite Four.

She properly debuted in Top-Down Training!, where she was first seen battling against Lucian with her on television. She then arrived in person in Amity Square, where she was studying ancient tablets. It was here that she met, , and Paul, who rushed down to Amity Square after they heard rumors of Cynthia being there. Paul challenged her to a Full Battle, but Cynthia won easily. She then mentioned that she was just like Paul in her youth, determined to win with the strongest Pokémon. After the battle, because Nurse Joy was busy, she and personally healed Paul's Pokémon, after convincing him to take them to a Pokémon Center. After this, back at the Amity Square Ruins, she explained something written there means very much to her: "When every life meets another life, something will be born". Later, Ash would think about this quote from time to time. Cynthia then decided to go to Celestic Town, where she planned to study the legend of, , and the Lustrous Orb.

In Losing Its Lustrous! and Double Team Turnover!, Cynthia, along with Ash, his friends, her grandmother Professor Carolina and Officer Jenny's police officers, tried to stop Team Galactic from stealing the Lustrous Orb at Celestic Town.

In Aiding the Enemy!, Cynthia battled to defend her title of Champion of the Sinnoh region on television, which she won. Ash and his friends commented that while Aaron was strong enough to be a member of the Elite Four, Cynthia was still far stronger than him.

In The Needs of the Three! and The Battle Finale of Legend!, Cynthia helped Ash and his friends protect the lake guardians and put a stop to Team Galactic at Spear Pillar.

In Four Roads Diverged in a Pokémon Port!, revealed that he intended to challenge Cynthia for her title of Champion.

In An Old Family Blend!, Cynthia observed the Lily of the Valley Conference alongside Charles Goodshow, making her the first current Champion to appear at a Pokémon League Conference. While watching, she showed a deep interest in the battle between Ash and Paul. At the end of the competition, she personally delivered the trophy to the winner,, who had won the Sinnoh League and the right to face the Elite Four.

In Memories Are Made of Bliss!, Ash and his friends watched her battle with Flint for the title of Champion. Flint's Infernape managed to defeat two of her Pokémon, but Garchomp ultimately defeated Flint's Infernape, earning Cynthia the victory.

Cynthia also had a cameo appearance at the beginning of Arceus and the Jewel of Life, where she was engaged in a battle against. In addition, Cynthia made a cameo appearance in the ending credits of Zoroark: Master of Illusions.