Misty (ミスティ, Misuti) is 4th Gym Leader of Cerulean City's Gym, known officially as the Cerulean Gym. She or her sisters hands out the Cascade Badge to Trainers who defeat either of them. She specializes in Water-type Pokémon. She leaves her post to her older sisters to be a friend and traveling partner of Ash Ketchum.
A stubborn tomboy, Misty is the youngest of four sisters who live in the Cerulean Gym. Fed up with her more glamorous older sisters, Misty left the Gym with the goal of becoming the world's greatest Water Pokémon Trainer.
During her travels with Ash, she, aside from training to become the best Water Pokémon Trainer, also acted as his coach in many Pokémon battles. She is somewhat considered as a rival to Ash due to their competitive nature.
Misty can be sweet and optimistic at times, but she is best known for how easily she can be angered, crazy, or frustrated, and how loud and violent she can become in response. She is very extreme in most of her moods, and can switch between them quickly. There are many episodes where she is seen getting along with the younger siblings of the family, namely Chris, Mikey, Sakura, and Max. This stems from the fact that she understands what it's like to be the youngest because she has three older sisters.
Her goals are not as clear as those of the other main characters, since though her main interest is training Water-type Pokémon, there are many things she loves to do and she is very confident in her abilities in all aspects of life. Fishing is one of her hobbies, however, and she has a special lure which she designed to look like herself and gave to Ash as a gift. The one Pokémon type that Misty cannot stand are Bug-types; she tends to freak out in most cases whenever she encounters a Bug-type, which was first demonstrated when she refused to befriend Ash's Caterpie. However, bugs are only one of three things Misty strongly dislikes, the other two being carrots and peppers. The only Bug-type Pokémon Misty is not afraid of are the kinds that she deems "cute" or "pretty", like Ledyba and Butterfree, some belonging to her friends, like Tracey's Venonat, or ones that don't look like bugs, like Pineco.