Age: 15
Blood Type: A
Height: 145 cm
Weight: 35 kg
Birthday: February 21

The main character of the story, she currently resides in room #4 of the Ayakashi Kan and is the master of Miketsukami Soushi. Ririchiyo is constantly in distress about not being able to communicate with people properly and decided to move to the Ayakashi Kan in order to be alone. She later befriends Karuta and Watanuki who both attend the same school and live in the Ayakashi Kan. She is the first character in Japanese anime and manga to be classified as a tsunshun instead of tsundere because she gets depressed (shun) instead of getting modest (dere) after behaving in a conceited manner.

In the end, she confesses to Soushi. She also promises to bear his child in the future.

In the future where everybody except Sorinozuka dies, she goes to Ayakashi Kan and resides in the 1st floor with Miketsukami as her SS. Since the first time she meets Soushi and a 41-year-old Sorinozuka she starts to get visions of her past life until Kagerou forces her to remember everything.

Although she doesn't love the current Soushi because her only love was the previous Soushi, she nearly died protecting him from a cursed Karasuma Kuroe.

Since they decided to send letters to their past selves to warn them about Inugami, everything that happens after the time capsule event in anime episode 12 will be rewritten and Ririchiyo won't confess to Soushi yet.