Kuune commands the Catian mothership sent to Earth for alliance negotiations, acting as both Eris's superior officer and the primary diplomatic negotiator. She possesses purple fur, cat ears, and a tail, standing 1.7 meters tall including her ears, with measurements of 100-65-90 cm (bust-waist-hips) and weighing 27.2 kg. Among Catians, she has the largest bust size, which causes her discomfort during formal talks when wearing Japanese school swimsuits—attire she professionally endures due to Eris's erroneous suggestion until negotiations conclude.

Her personality merges approachable warmth with stern command. She displays childlike excitement for Earth's culture, particularly Okinawan cuisine and anime theme songs, often reacting to meals with vocal enthusiasm. During diplomatic sessions, however, she adopts a calculated, unyielding stance, skillfully steering human officials away from unfavorable terms while avoiding concessions. This reliance on subordinate input sometimes triggers cultural missteps, exemplified by the swimsuit incident. A defining trait is her silver captain's bell, an enhanced device surpassing standard Catian communication bells. It operates as an advanced organizer, materializes objects, and weaponizes atmospheric particles via rapid freezing—though she seldom employs its offensive functions.

In the series' central conflict, Dogishuin forces assault the Catian Embassy, infecting Kuune with a nono-machine virus that paralyzes her. To defend the mothership, she transfers her captain's bell to Kio Kakazu, granting him tactical command. After post-battle recovery, she resumes her duties while acknowledging Kio's pivotal role in safeguarding the vessel and diplomatic mission. Minimal personal history is documented, though trivia notes her birthday as February 2.