Saki is Yuuji's cousin and Keijiro's niece. Yuuji stays with her and her father Takeaki while he attends Sakuragaoka Academy. Saki can be rather violent. She wields devastatingly powerful punches and kicks and is skilled in wrestling moves. Her favorite move is the German Suplex.
Saki is not very good at studies but is a good homemaker. She wakes up early every morning to make breakfast for her family. She will also wake Yuuji up using creative and painful methods.
A few months after Yuuji moved in with them, Saki thanked him for brightening their life and being a good friend of Sumiyoshi.
On Saki's path, Saki revealed that she has been in love with Yuuji since they were 5 when they attended their aunt's wedding at the Yukito Shrine. Saki was revealed to be the girl that Yuuji remembered seeing under the Snow Sakura tree.
Saki revealed that she wanted to re-open the Tachibana Inn. Rei and Sumiyoshi revealed that they were childhood friends of Saki. They noticed that Saki had hid all the photos of her mother. Saki later revealed that she greatly misses her mother.
One day, Saki decided to be open about her relationship with Yuuji. Rei warned her to not be too public at school. The Vice-Principal noticed and rumors started to spread. The Vice-Principal called them in as well as Misato and Takeaki. He decided to separate them to preserve the school's image and suspended Yuuji from school for a week and commanded Saki to live with Rei.
Saki became depressed and Misaki suggested that they share a diary and the group will take turns delivering it between her and Yuuji. After a week, the Vice-Principal commanded Yuuji to move out of the Tachibana Inn. Takeaki then presented a video tape of Keijiro agreeing to Saki's and Yuuji's marriage engagement. The Vice-Principal was forced to concede.
Saki married Yuuji after they graduated. They re-opened the Tachibana Inn 2 years later.