Kiki, often referred to by the nickname Appendix Kiki, is a young apprentice and disciple of the Gold Saint, Aries Mu. A cheerful and lively boy who often takes things lightly, Kiki is distinguished by the two tilak dots on his forehead, a mark he shares with his master and which signifies his heritage as a member of the Lemurian or Muvian race. He is originally from Tibet and trains in the mountains of Jamir, learning the arts of his master from a very young age.

In the narrative of Battle for Sanctuary Part 2, Kiki serves as a supportive figure, remaining close to Saori Kido, the reincarnation of the goddess Athena. During the ninth hour of the battle, he decides to stay and watch over her alongside Tatsumi. Throughout the conflict, he shows his concern for the Bronze Saints fighting to protect Athena. His youth and inexperience do not prevent him from facing the gravity of the Sanctuary's civil war; he has a pragmatic side that allows him to cope with stress. During the twelfth hour of the battle, he admits to Tatsumi that his playful and joking nature is a personal way to relieve the immense pressure of the situation they are facing.

Kiki's primary role is that of a helper and messenger. His most defining trait is his powerful telekinesis, a psychic ability he can use to move objects and even humans with his mind, although he does not engage in direct combat. He puts this ability to use in service of Athena's Saints. His most significant relationship is with his master, Mu, to whom he is completely loyal and whom he assists with various tasks, such as delivering repaired Cloths. He also develops a strong camaraderie with the Bronze Saints, particularly the Dragon Shiryu, whom he has known since the beginning of his journey. Kiki's development in this part of the story shows him taking on more responsibility, moving from a simple comic-relief child to a reliable ally who actively chooses to protect the goddess and aid the warriors in their quest.