|Kyouko Tachibana (橘京子)|
|Introduced In||The Intrigues of Haruhi Suzumiya|
Kyouko is speculated to be near the same age as the SOS Brigade, and Kyon describes her as a woman of his age. (In The Dissociation of Haruhi Suzumiya, she is most likely in her second year of high school.)
At around the same time the 'Agency' formed, a "rival" group formed, including people such as Kyouko Tachibana. Her group firmly believed that their powers had, in fact, come from Sasaki, and went searching for her. Conflict broke out between the two groups, and despite numerous meetings neither could convince the other side. The rivals believe that the powers were accidentally transferred to Haruhi Suzumiya.
Kyouko first appears alongside Fujiwara in The Intrigues of Haruhi Suzumiya, in which she helps kidnap Asahina Mikuru; while this plan fails, she convinces Fujiwara, a time traveler, to stay as an ally.
Tachibana believed her group needed the support of a time traveler and alien, just like the SOS Brigade, and was eventually able to assemble the group.
In the beta plot, Sasaki called Kyon for a meeting on Saturday evening with the rest of her compatriots. Despite misgivings, Kyon consented to the meeting.
Kyouko tries to convince Kyon that he should transplant Haruhi's powers into Sasaki as she believed Sasaki had a more stable personality, but confessed that the other members of the group, even Sasaki, showed little interest in this. She tried to convince Kyon by showing him her closed space which she said was "calmer than Haruhi's," but when he does not take well to the idea, she becomes very annoyed.
She is shown to be the most enthusiastic about making Sasaki the one with the godlike powers and is most likely to be the most progressive in attempting so.
She also claims that the incident taking place in The Intrigues of Haruhi Suzumiya was a mistake on her part, adding that she was influenced by Fujiwara.
After Nagato fell ill, Kyon demanded another meeting, which was held Tuesday after school. Tachibana tried to smooth over friction in her own group, but it didn't really work. Fujiwara insulted her repeatedly. Kyon refused to fall for Fujiwara's blackmail, but Tachibana wasn't ready to give up. She suggested that if Haruhi lost her powers, the rest of the Brigade would disband, but Kyon could hang out with Sasaki and still enjoy a supernatural-affected life. She told Kyon that Koizumi founded the 'Agency' and this action would relieve his burden.
Even when Kyon hadn't reconsidered, Tachibana left the meeting saying she would give him time to think it over.
Toward the end of The Astonishment in the α and β timelines, Koizumi comforts a depressed Kyouko after the two of them were in Sasaki and Haruhi's merged closed space and they exchanged phone numbers and emails in order to keep in touch with esper-related issues. Tachibana resigned from her group.
- Tachibana refers to a type of inedible wild orange. It is also the name of two famous clans in Japanese history.