Rainbow Dash was a somewhat aggressive and competitive pegasus. She presented as someone who thought highly of herself, but secretly was very insecure. She cares deeply for her friends and is motivated by them.
Rainbow Dash had a light blue coat, magenta eyes, and a colorful mane - a red, orange, and yellow forelock with a green, blue, and purple crest. Her tail has all six colors in rainbow order. Her cutie mark was a white cloud with a single bolt of lightning coming out striped red, yellow, and blue.
Earlier G5 ideas featured redesigns of the Generation 4 characters from the cartoon. Rainbow Dash keeps her species and blue coat, but her rainbow elements are played with. Some concept art adds rainbow secondary feathers, and some mess with the order of the colors in her mane. Some concepts give her golden shoes and accessories, giving her a Roman Warrior feel. The manner in which she is drawn conveys a similar personality to that of her G4 edition.