Theory: Ayako

The following fan theories are about Ayako.

Theories

Theory	Citations	Notes
Ayako was the daughter of Sakuya Haibara and Yo Haibara.	Her family name was kept a secret in Rogetsu Hall.	+ She had a very close relationship with Yo: her room connected with his; he mentioned her frequently in his diary; he wanted to live with Ayako and Sakuya together; he was one of the people she mentioned in her Torn-Up Note alongside her mother, referring to him as "Yo-chan". + Shigeto mentions that Yo and Ayako have similar traits. + In two documents, Yo wishes that he, Sakuya and Ayako could live together away from the island. + Ayako is one of the three people Sakuya says goodbye to in what may have been her last diary entry. The others are Yo and Shigeto. + One of Ayako's entries in the spirit list (#41) mentions her "unnatural blood". + Ayako's name shares a character (夜) with Sakuya's. This is relatively common for parents and children (eg, Ruka and Sayaka both use the character 歌). - According to the ages given in Choshiro's notebook, Yo Haibara would have been only fifteen when Ayako was born.