Ruu

Chapter 34
A silhouette of Ruu appeared behind Yuuri when she was looking out at the city. Sometime later, Yuuri tells Yuki about her younger sister, Ruu. She explains that Ruu was so small and could easily get lost, and afterwards, Yuuri realizes that she had forgotten about her and had accidentally replaced her with Yuki, making her very depressed.

Chapter 35
After Miki and Kurumi found Yuuri exiting the Namekawa Grade School, she pulls out Ruu hiding behind her, much to the others shock. Yuuri explains to Ruu that Kurumi and Miki were her friends, so she didn't have to worry. The four return to the RV and Yuki appears and starts interacting with Ruu.

Chapter 36
Yuuri was dissusing some things with Ruu if she remembered her name, but she failed to answer. However, Yuuri wasn't bothered by this and instead told her to call her "Rii". Ruu wanted to say something, but she was unable to say it; but Yuuri reassured her that she didn't need to rush. As Yuuri didn't know her name either, she therefore came up with the name "Ruu". Yuki then appeared and started to greet her with some silly actions, to which Ruu hides behind Yuuri and looks weirdly at Yuki. When Yuki performed some silly actions whilst Yuuri explained that she is a very funny girl, she is still a little cautious of her. In the RV, Miki only mentions Ruu as she wasn't sure how to greet her, but Kurumi told her to treat her the same was as Yuki.

Later, Yuki, Yuuri and Ruu went back to the RV and started eating. When Yuuri was feeding her, Yuki played with her food by stuffing the food in her mouth, making her cheeks very big. Though Yuuri told Ruu to not act like Yuki as it was a "bad" thing, Ruu immediately imitated Yuki's action, much to Yuuri's chagrin. Yuki took great pride in this.

At night, Yuuri and Ruu were sleeping at the same bed, so when Ruu started screaming (possibly from a nightmare or the trauma she suffered) Yuuri hugged her ad reassured her that it was okay and that she would never leave her. The following day, the girls continued their journey to Saint Isidore University. When they arrived at the university, they were approached by an unnamed boy, and he told them to drop everything and put their hands up. The girls did as they said, but Yuuri still had her arm around Ruu, causing him to fire the crossbow directly aimed at Yuuri and Ruu.

Chapter 37
The attack was directly aimed at Yuuri and Ruu, but Yuuri protected Ruu with her body; ready to take the hit, but Kurumi blocked the attack with her shovel right in time, shocking the boy. Kurumi then told him that they weren't infected, and asked him if it would be okay if they just go back, and then he tells them to hurry and go. They then went to the RV and started treating Yuuri, with Ruu sitting besides her. When Yuuri asked Ruu if she was scared, she didn't answer, but Yuki stated that she probably wasn't, as Yuuri was there. Ruu then fell asleep at Yuuri's shoulder. They then decided to explore outside, but only Kurumi and Miki went as the boy tried to attack Ruu, a child; without any hesitation. When Yuki told her that she would also watch the house and that they should do their best, Ruu woke up. They then started to playing and interact with each other, until Kurumi and Miki came back rushing as they had two unnamed pursuers behind them. The girls went in to the RV and started driving, and Yuki told Ruu to put her seat belt on, and thereafter, they arrived at the Saint Isidore University exit, where they met three new girls, Touko Dekuchi, Aki Hikarizato and Hikako Kirai.

Chapter 38
Ruu, along with the School Life Club went to the school with the new girls and their club room. Ruu, as well at the others rested a bit as they were very exhausted. They then went to another room, where everyone started introducing themselves, but Ruu didn't say anything under the whole introduction and discussion, so Yuki introduced Ruu instead.

At night, the School Life Club members and Ruu decided to sleep at Yuki's room (everyone got their own room, whilst Yuuri and Ruu shared a room), and when Yuuri asked Ruu if she was okay with it, she nodded. Yuki thanked both Yuuri and Ruu, and thereafter, everyone went to sleep.

Chapter 39
Yuuri and Ruu were in a classroom, Yuuri was cleaning while Ruu spectated. When Ruu sees Yuuri putting up a sign at the door reading: School Life Club club classroom, she asks "Classroom?". Yuuri tells Ruu that students still have to study, even at universities. When Yuuri spotted Yuki, she told her that she should study too, so the girls went to the room; and while Yuki and Yuuri studied, Ruu was reading a book. The girls were thereafter joined by Kurumi.

Chapter 40
The School Life Club club member and Ruu went to discuss some things with the members of the Fallen Crew, Touko, Aki and Hikako (Hika). Ruu didn't say much, as she was only sitting and Yuuri's lap and listened. When the group started talking about to maybe go outside to see Randall Corporation, Yuuri asked Touko if they only had to focus on Randall, and that if it would be okay if they could stay at the university a little longer, to which Touko agreed to; as Yuuri doesn't want to put Ruu in danger.

Later that day, Yuuri and Ruu were walking through the corridors, when suddenly Ruu froze up and began to panic a little, but Yuuri realized this on an instant and immediately comforted and embraced her. When Ruu looked up at her in surprise, calling her "Yuuri", she tells Ruu to call her "Rii-nee san" instead, and she then asks her if she would like something to eat, to which Ruu happily agrees to while smiling, calling her older sister "Rii-nee san".

Chapter 41
Ruu was present at a meeting with both clubs and Touko explained the School's areas and so on. After that, Ruu, Yuki, Yuuri and Miki goes outside, and Ruu and Yuki started playing with each other, as Yuki was carrying Ruu on her shoulders; showing that Ruu has clearly become more happy. Yuuri talked with Miki about how energetic Ruu had become, but Yuuri then starts telling her that she's scared that Ruu might leave her one day, or that one day she won't be by her side anymore, but Miki comforts Yuuri, cheering her up a little.

Chapter 42
Ruu was once more present at a meeting, and she was sitting at her sisters lap (like always). Touko explained that they would go outside, and as stated by Yuki to, to go on a Field Trip, but actually camping as they were university students. Upon hearing this, Ruu becomes a little unsure and pulls Yuuri's shirt, but she reassures her it would be okay, and pats her head. When Hika tells everyone that there has to be some people staying at the school, Touko explains that everyone might get separated, with Yuuri infoirming Touko that she will stay behind. When Yuki asks way, Yuuri tells her that her reason is Ruu, as she cannot take her. The Fallen Crew produces some weird expressions upon hearing this.

Later that day, Miki carried Ruu sleeping, to Yuuri as she had taken care of her while Yuuri exercised and showered. She thanked Miki and took Ruu, and when Miki asked if really wasn't going to camping, Yuuri replied that even if the camping was important, she couldn't take Ruu no matter what.

Chapter 43
Ruu was sitting on Miki's lap in a classroom as the others (Yuki, Kurumi, Touko, Aki and Hika) were organizing things. Yuuri later spotted them and waved towards Ruu and Miki, and they waved back. Yuuri then stayed by Ruu's side the rest of the day.

Chapter 44
Ruu, Yuki, Miki, Yuuri, Kurumi, Rise, Aki, Hika, and Touko started celebrating and decided to have a party, because they had just finished preparing for their trip. Yuki asked what Ruu would like as a present, but as a result, Miki looked at them a little worried. At night in their room, Ruu worriedly calls out to Yuuri, but she tells her that everything would turn out fine.

Chapter 47
Ruu makes a very small appearance as she peacefully watches her older sister Yuuri sleep.