Birdo

Birdo, known in Japanese as Keith (キャサリン, Kyasarin, [kʲa.sa.ɾiɴ]), is a fictional character in the Mario franchise. Her first appearance was as an enemy in Yume Kōjō: Doki Doki Panic, which was localized for English-language audiences as Super Mario Bros. 2. Since then, Birdo has been a recurring character in various franchise spin-offs. Initially, he was depicted as an antagonist, but has since been depicted as an ally. Birdo has also made several cameos, particularly in the Mario Kart series and the Japan-only Wii video game Captain Rainbow.

The English manual for Super Mario Bros. 2 refers to Birdo as male, “who thinks he is a girl" and would prefer to be called "Birdetta". Some take that as a representation of Birdo as transgender, making her the first transgender video game character. Later releases of Super Mario Bros. 2 removed all mentions of her favored nickname. Starting with Mario Tennis, Nintendo has treated Birdo as just female and depicted her as romantically involved with Yoshi.

The character has received mostly positive reception in the Mario series, although her appearance and gender identity have received mixed reception. She has made several appearances in other media, including the Super Mario Bros. Super Show!, as well as promotional material such as figurines and plush toys.