"My brother was murdered by this country! This country needs to be destroyed!! Those who run this country... The system they're created... All of it!"
Sayuri is a light hearted individial, yet dedicated to her work, especially when it has to do with the safety of the Takagi family. She and Haruka have an almost sisterly relationship. She suddenly becomes cold and emotional once her true identity is revealed.
Sayuri is first introduced shortly after Fujimaru's father is forced into hiding when being suspected for the murder of the district chief of Third-I. Team Takagi assigns her to protect the Fujimaru family in case the terrorists attempt to kidnap Fujimaru.
While watching Haruka during her dialysis, she is shot in the chest by Jack Daemon. Only surviving because of her bulletproof vest, she quickly joined forces with Fujimaru and the others to attempt a rescue. Shortly after it is revealed that the terrorists likely have a spy within the ranks of Third-I.
Later on, while Maya is in custody and is attempting to make a plea deal. Sayuri, Fujimaru, and Kanou transport Maya to a location of her choosing. Upon arrival, Fujimaru reveals that he believes Sayuri is the spy. Among other things, she never revealed the existance of the virus to the higher-ups, and an expert like Jack Daemon would have shot any enemy in the head to confirm the kill. The only reason he left her there was because he knew she had a vest one and she was an ally of his.
Sayuri and Maya gain the upper hand in a short fight and stand off, which results in Sayuri shooting Kojou in the head (with a gun she didnt know contained rubber bullets). Maya leaves with the captured Fujimaru while Sayuri returns to Haruka and Otoya, to kill them if Fujimaru fails to accomplish the job the terrorists. Third-I reveals that she is a spy over the intercom and she shoots Otoya (again with rubber bullets) and escapes to the rooftop with Haruka as a hostage.
When Haruka asks why Sayuri would betray the Fujimaru family and Third-I, she reveals that her brother was shamed and commited suicide. He worked for the government and took the fall for his boss who was embezzeling money. He was eventually driven to suicide, which Sayuri blamed the Japanese government for his death, causing her to join the terrorists as a means for her revenge. Once Kojou is revealed to be alive and she knows there is no means of escape, she claims "there's no where for me to return to" and motions to jump from the building, allowing herself to be shot by snipers.
- She is played by Nana Katase in the live action drama.
- She is 165 cm tall, blood type O, and a Sagittarius.
- Her favorite food is yakitori.