Kyoko was an amnesiac and was titled as Ultimate ??? at first. Later, it was revealed that her true identity is the Ultimate Detective (超高校級の「探偵」 chō kōkō kyū no “tantei”) She is also the daughter of Jin Kirigiri, the deceased Headmaster of Hope's Peak Academy.
In Chapter 5, the mastermind attempts to have her executed for the murder of Mukuro Ikusaba, a crime she didn't commit, due to her interference in the mastermind's plans. However, Makoto Naegi sees through this but is almost executed himself, which was stopped due to the interference of Alter Ego. If the player chooses to call out her lie, Kyoko will be executed in the bad ending.
Kyoko survives the final trial and escapes Hope's Peak Academy with the other survivors.
Kyoko also appears in Danganronpa 2: Goodbye Despair as a member of the Future Foundation, along with Makoto and Byakuya Togami. She's also seen in Danganronpa/Zero.
A light novel series based on Kyoko's past with Yui Samidare has been published, titled Danganronpa Kirigiri. Kyoko also returns in the spin-off manga of Danganronpa 3, Danganronpa Gaiden: Killer Killer.
Kyoko returned in Danganronpa 3: The End of Hope's Peak Academy and is the leader of the 14th Division.
Kyoko was poisoned after her NG code was unintentionally triggered by Makoto. However, it is revealed that Kyoko had taken some of Seiko Kimura's medicine, allowing her to temporarily stall the poison by falling into a comatose state and later be revived by Mikan Tsumiki. She is one of the five survivors of the Final Killing Game.