A small white-grey kitten with whiskers, pale blue eyes, pale pink ears on the inside, and a light blue collar with a yellow bell on it.
Diana is the guardian feline to Chibiusa Tsukino. She is a female kitten from the 30th Century. She is the daughter of Luna and Artemis in the future. She stays by her beloved King's side and is determined to do whatever she can to save their homeland. Diana and Chibiusa were the only ones who were unscathed by the attack on Crystal Tokyo. Diana is described by Sailor Pluto as kind and thoughtful.
Act 19 - Chibiusa is happy to see Diana alive.
Act 20 - Diana informs Chibiusa that King Endymion has been watching over her from the shadows the whole time she was in the past. Once disaster hit Diana choose to stay rather than go with Chibiusa to the past, never leaving her parents side.
Diana sleeps next to her unconscious parents.
Act 24 - Diana runs to tell Sailor Pluto all the terrible things that have happened; Chibiusa grew-up her power awoke and now she's Black Lady, Nemesis appeared via another dimension and is about to crush the Crystal Palace. Diana offers to watch the Space-Time Door as the guardian in her place so Sailor Pluto can join the fight. Diana knows she is tiny and has no powers but she can still guard the Space-Time Door.
Act 25 - Sailor Moon, Sailor Mercury, Sailor Mars, Sailor Jupiter, Sailor Venus, Tuxedo Mask, King Endymion, Sailor Chibi Moon, Luna, Artemis and Diana get trapped in distorted space by Death Phantom.
Act 26 - Sailor Mercury, Sailor Mars, Sailor Jupiter, Sailor Venus, Tuxedo Mask, King Endymion, Sailor Chibi Moon, Luna, Artemis and Diana return to 30th century Earth without Sailor Moon.
Both Sailor Moon and Neo-Queen Serenity run to meet each other, those of the past and those of the future stand at a short distance from each other. Neo-Queen Serenity, King Endymion, the future Inner Senshi, future Luna, future Artemis and Diana see off Sailor Moon, Tuxedo Mask, the past Inner Senshi, Luna and Artemis as they return to the 21st century.
Act 27 Part 1 - While eating breakfast with Diana, Chibiusa hears a news-report about an unidentified monster that could be a result of atavism.