Misty

Misty (known in the Japanese version as Kasumi) is the Gym Leader of Cerulean City. Trainers who defeat her receive the Cascade Badge. In the anime, she travelled around with Ash, Brock, and Tracey through the Kanto region, Orange Islands, and Johto region. After Ash was done in Johto, though, she returned to Cerulean to watch the Gym while her sisters, Daisy, Lily, and Violet, went on a world tour. Misty used to hate Gyarados because of a traumatic experience as a child, but now she's okay with them.

In the manga series Pokémon Special, Misty was the partner of Suicune in the battle against Team Rocket in Johto. She seems to have a crush on Red. This is distinct from Misty's believed crush on Ash, which there isn't very much evidence for outside of the dubbed version of the Pokémon anime.