Kiki serves as apprentice to Aries Mu, sharing the distinctive tilak dots of his master and grandmaster Aries Shion. This Tibetan youth trains at Jamir in the Himalayas. As a Lemurian descendant, he stands as the youngest depicted within the series. Despite his youth, Kiki wields significant telekinesis, employing it for moving objects and aiding allies while avoiding direct combat. His playful, mischievous nature surfaces early, using his powers for pranks like those against Shiryu at Jamir or during a children's soccer game.

Throughout the Poseidon conflict, Kiki actively supports the Bronze Saints. He delivers their repaired Cloths to Rozan and later transports the Libra Gold Cloth underwater, enabling the destruction of the Mammoth Pillars. He fiercely defends the Cloth against Marina Generals Thetis and Kraken Isaac, shielding it with his body and sustaining injuries. His tracking skills, particularly using his sense of smell, help locate enemies. During this period, he adopts the self-proclaimed title "Appendix Kiki."

Kiki's role proves critical during the Hades arc's invasion of Elysion. He detects the direction of attacks launched by Thanatos from Elysion targeting Seika, Seiya's sister. Alongside Silver Saints Marin and Shaina, and Bronze Saints Jabu, Ban, Ichi, Geki, and Nachi, he forms a protective barrier around Seika. The group collectively intercepts and absorbs the god's strikes, shielding her despite being overpowered. Kiki later witnesses the conclusion of the "Greatest Eclipse," signifying Athena's victory.

In the spin-off *Saint Seiya Omega*, Kiki matures into the Aries Gold Saint, succeeding his master. Residing in the Aries Temple as an adult, he mentors his own apprentice, Raki. He remains the world's foremost Cloth repairer, dedicated to restoring and enhancing the Cloths of the new generation of Bronze Saints like Pegasus Koga. During the war against Mars, he openly defects from Mars's control to aid Koga and his allies, repairing their Cloths and revealing Mars's plan to drain Earth's energy. He holds off Martian soldiers to facilitate their passage through the Twelve Temples. Later, in the conflict with Pallas, he repairs Cloths on the battlefield, confronts the Pallasite assassin Dione, and escorts Athena into Pallas's domain. His abilities expand to include crystal manipulation, teleportation, atomic destruction, and advanced techniques like Stardust Revolution and Starlight Extinction.