Yotsuha Miyamizu

Yotsuha Miyamizu (宮水 四葉) is Mitsuha's younger sister, they live together with their grandmother. Yotsuha helps out in the family shrine, performing ceremonies with her sister.

Appearance
Yotsuha is a young girl with light brown eyes and black hair which she wears in pig tails with two different hairbands. She is usually seen wearing a blue T-shirt with an orange hoodie on top, white shorts, pink-colored knee-length stockings and brown shoes.

As a teenager, Yotsuha grows out her hair but still wears it in pigtails with two hairbands. She is seen attending high school with a standard uniform.

Personality
Yotsuha is very level-headed and independent, always waking her sister up in the morning and helping with breakfast, but she still acts a like young girl her age. She is quite carefree with the things surrounding the Miyamizu traditions which Mitsuha describes as "pre-pubescent lack of concern". However, she seems to be tired of the traditions, like making braided cords at times, like her sister. She also isn't very aware of her sister relation to their father, but she knows they aren't on very good terms as she wants them to make up. Mitsuha mentions that Yotsuha comes up with many, and at times, weird ideas. She thinks that Mitsuha is somewhat crazy but loves her despite the situation.

Like most of the other Itomori residents, Yotsuha speaks with a dialect, often havin the suffix -ya in her sentences.

Background
Yotsuha is the second child born to Toshiki and Futaba Miyamizu. Yotsuha had a happy childhood with her parents and older sister, but that changed when her mother died to a disease when Yotsuha was very young, thus leaving her to not remember much about her mother. When their father leaved the shrine to persue politics instead, Yotsuha along with Mitsuha began living their grandmother.

Plot
Yotsuha is commonly seen during the movie waking up Mitsuha, and, if Taki is in her body, expressing her discontent at her 'liking her boobs'.

When Taki is able to switch one more time with Mitsuha, his crying fit makes Yotsuha leave, muttering that Mitsuha has gone mad and had 'lost it'.

She inadvertently revealed to Taki (while he was in Mitsuha's body) that Mitsuha skipped school one day to go to Tokyo and look for him. She expresses genuine concern for her sister following the trip.

Following the destruction of Itomori, Yotsuha migrates to Tokyo, presumably with her family members, since Itomori was destroyed. She is seen attending high school in the city.

Trivia

 * Her name "Yotsuha" (四葉) means "four leaves". The same applies to her grandmother Hitoha, that means "one leaf"; her mother Futaba, "two leaves"; and her sister Mitsuha, "three leaves".
 * It is unknown with whom she lives at the end of the film, as Mitsuha is seen living alone in her own apartment. Presumably, Yotsuha lives with her father and/or grandmother.