Nepu is the nickname and catchphrase of Neptune, the cheerful protagonist of Hyperdimension Neptunia, the role playing game series that began in 2010. Fans clipped her short excited vocalizations from the games and anime adaptation and shared them on soundboards and in fan edits. The name stuck because Neptune repeats Nepu as a verbal tic, making even a fraction of a second instantly recognizable to players. The clip remains popular in anime and gaming communities as a quick shorthand for innocent, hyperactive excitement.