The Tachibana Family is a family referenced in Fatal Frame II: Crimson Butterfly.
Although the player spends a good amount of time in the Tachibana House, only three members of the family are directly referenced. They are the twin sons, Itsuki and Mutsuki Tachibana, and their younger sister, Chitose Tachibana.
Mutsuki Tachibana was killed by his brother Itsuki as part of the Crimson Sacrifice Ritual. Their ritual was a failure, however, so his death was in vain.
Itsuki Tachibana was the Remaining after killing his brother, Mutsuki, in the Crimson Sacrifice Ritual. The trauma of killing his brother caused his hair to turn white. He is locked up in the Jailhouse in All God's Village and helps Mio throughout the game. He committed suicide by hanging himself in his cell after helping Sae and Yae escape.
Chitose Tachibana is the younger sister of Itsuki and Mutsuki. By reading the Crimson Diaries found in the Tachibana House, one can assume that she was very close to her older brother Itsuki. She had very bad vision and would get lost a lot, calling out to Itsuki to come help her. Itsuki had given her a bell to wear, so he would always know where she is. When encountered, she mistakes Mio for Yae crying, "Give me back my brother!", obviously blaming her for Mutsuki and Itsuki's misfortune.