Diana is a feline character from the future era of the Silver Millennium. Born to Luna and Artemis, her light grey fur visually merges her parents' black and white coloring. In this future timeline, she fulfills the role of dedicated advisor and constant companion to Chibiusa (Usagi Small Lady Serenity), typically remaining by her side except during Chibiusa's travels to the past. Diana appears as a supporting mascot character in *Pretty Guardian Sailor Moon Crystal: Season III*, specifically listed among the mascots in the final episode (Act 39) alongside Luna and Artemis. She maintains this position in the sequel film *Pretty Guardian Sailor Moon Eternal*, accompanying Chibiusa and the Sailor Guardians in their conflict against the Dead Moon Circus. Across both the series and film continuations, Diana consistently serves as Chibiusa's faithful companion within her established supportive role.