Diana, born to Luna and Artemis—feline companions of the Sailor Guardians—inherits her light gray fur from the mingled hues of her parents’ black and white coats. As a devoted advisor and companion, she aligns closely with Chibiusa, the future daughter of Usagi Tsukino and Mamoru Chiba. In *Sailor Moon Eternal*, Diana joins Chibiusa’s attempt to journey back to the 30th century using the Space-Time Key, only to face obstruction by the Dead Moon Circus’s dark barrier. Stranded in the present, she aids in strategizing against their adversaries alongside Chibiusa, Usagi, and Mamoru within the command center hidden beneath Game Center Crown. Throughout clashes with the Dead Moon Circus, including battles against the Amazoness Quartet and their summoned creatures, Diana remains a constant ally. She prioritizes safeguarding Chibiusa, particularly during crises involving temporal instability or direct threats to her charge’s well-being.