"Ryosuke, you are wrong. Just look at Horii: He has short legs, he is fat, and he tells lame jokes all the time. He is a man filled with flaws. But despite all these flaws, everyone still loves him."
- ―Sayaka to Ryosuke, Requiem to the Darkness.
Sayaka Ijuin Ultraman Tiga. She is a member of the TPC Space Development Center.
is one of the supporting characters ofPersonality
Sayaka has an amiable and friendly personality. She often maintains good relationships with others and becomes a trusted confidant of her close friends. She will also do her best to provide support and assistance when her friends need help.
However, she also has a pessimistic side. Due to Ryosuke's tragedy, she had a more negative attitude towards reality, but she also made efforts to overcome this situation and try to believe in hope.
She seemed to have some affection for Ryosuke, but this feeling did not ultimately result in a relationship.
History
Pre-Ultraman Tiga
Five years ago, Sayaka was a college classmate of Ryosuke and Horii, and maintained a friendly relationship with them. During their time in college, Ryosuke had a crush on her, although she was not very aware of it.
Ultraman Tiga
Three months ago, Ryosuke told her that to avoid TPC's investigation, he was going to stay in a new type of resort for recuperation. Worried, she later goes to the resort to take care of him and thus unexpectedly reunites with Horii, who was conducting a biological reaction investigation there.

Later on, around the same time, Ryosuke invited her for a walk on the nearby beach, but due to the influence of his Evolu cells, he began to angrily vent his feelings of inferiority and helplessness. Despite Sayaka and Horii's attempts to comfort him after learning about the Evolu cells, Ryosuke continued to deny it and eventually completely broke down, transforming into Evolu and going on a rampage.
After Ultraman Tiga defeated Evolu, Ryosuke eventually died due to the side effects of his body's transformation. She and Horii were very saddened by the tragedy and it greatly influenced her future behavior. Requiem to the Darkness
To prevent tragedies like Ryosuke's from happening again, she joined the TPC Space Development Center and began searching for evidence of the fatal flaws of the Evolu cells experiment. During this time, she learned that the Center had saved data and documents on Evolu cells, and also discovered the targets of the Evolu cells' parasitic behavior, which not only granted abilities but also fueled hatred.
Later, she reunited with Horii who had come to investigate, but their friendly interactions led Michiru Ezaki, who was observing them in secret, to misunderstand their relationship.
When Metamorga attacked the Space Development Center to obtain high-purity energy, she commissioned Michiru to help her find the files on Evolu cells. However, due to the destruction of the Center, they were both trapped in the file room and were eventually rescued by Horii in a critical moment.

When the three of them were trapped in the building, the collapse of the structure caused Horii and Michiru to be injured. Witnessing the strong trust between the two, she made a heartfelt wish and in the end, with the help of Illusion Evolu, witnessed Ryosuke's soul and Ultraman Tiga defeat Metamorga.
After the incident, Sayaka announced the information to the outside world and successfully abolished the Evolu cell experiment completely. In the hospital, she told Horii that he must face his own feelings and encouraged him to accept Michiru's feelings. In the end, she attended Horii and Michiru's wedding as a guest. Goodbye to Darkness