Ran Ran, codenamed Judgment Princess, operates within the Secret Society Gekko's Princess Series under the command of Drone Rabbit. Her distinctive green hair and Korean martial arts attire mark her as the organization's sole foreign princess.

Trained intensively by Drone Rabbit in espionage, gadget development, and sabotage, Ran Ran's limited socialization opportunities fostered a withdrawn personality. She initially shuns interaction, frequently hiding her face and appearing aloof.

A pivotal moment occurs when Reaper Princess Desumi Magahara hosts a sleepover disguised as a strategy meeting. Attending initially in the guise of Fudo Aikawa, Ran Ran gradually participates in activities like eating takoyaki and discussing relationships. She later confesses to Desumi she enjoyed the event and expresses gratitude, marking her first step towards forming friendships.

Ran Ran's combat skills reflect her espionage background. She masters flawless disguise, replicating appearances and voices perfectly, and executes sabotage undetected, such as disabling the Gelato 5's weapons. Her signature special move, "Duàn Zuì Liè Lún," utilizes a spinning wheel on her back that transforms into a blue fiery disk launched at opponents.

Desumi Magahara becomes Ran Ran's first genuine friend, earning her sincere appreciation. Ran Ran remains a loyal subordinate to Drone Rabbit, providing assistance during crises like the Ultimate Phantom's attack on Gekko's base. Following the sleepover, she continues participating in group activities with other princesses, indicating growing social engagement. She is present during major Gekko events, including the Ultimate Phantom's creation and subsequent battles, demonstrating her ongoing commitment.