What was Kirby's original name during development?

During development, Kirby's original name was Popopo.

Popopo was the working name for the round, simple character created by Masahiro Sakurai at HAL Laboratory. Sakurai initially drew the character as a placeholder graphic while developing an early Game Boy platformer, but the design worked so well that the temporary-looking hero became the game's final protagonist. The project itself went through the working title Twinkle Popo.

Nintendo and HAL Laboratory later changed the character's name to Kirby for international appeal. The final name was selected from suggestions associated with Nintendo of America and is widely linked to John Kirby, the lawyer who represented Nintendo during its legal dispute with Universal Studios over Donkey Kong. In Japan, the franchise is known as Hoshi no Kirby, or Kirby of the Stars.

Popopo is sometimes confused with Twinkle Popo because both names appeared during development. They are related but not identical: Popopo was the character's early name, while Twinkle Popo was the planned title of the game. Kirby's Dream Land was ultimately released in Japan in 1992, introducing the character to players worldwide.