Mashiro is a world famous artist. Unfortunately, she knows nothing other than drawing, resulting in an extreme lack of living ability and common sense.
Mashiro Shiina is created by Hajime Kamoshida as one of the main characters in the Pet Girl of Sakura Hall franchise. She is the female protagonist of the anime show The Pet Girl of Sakurasou (Sakurasou no Pet na Kanojo). At this moment, there is no information regarding any inspirations that Kamoshida used to create Shiina. She is voiced by Ai Kayano.
Mashiro is a beautiful girl with long, blonde hair that flows past her nape and shoulders. She has slanted, amber eyes with pupils. Her school attire consists of a blue jacket over a light blue vest, a white, long sleeved shirt, a red tie, and a pink skirt.
Typically, she expresses little emotions and speaks quietly. Mashiro is a genius world-wide painter. She spends all her time on doing manga. She is a strange one because she does not know how to take care of herself, and her bluntness in talking can generate lots of misunderstandings as demonstrated with her relationship between Nanami. She does express jealously when she remarks how Sorata includes Nanami in his presentation conversations.
Sorata is Mashiro's first male friend. At first, Mashiro wants Sorata to call her by her first name. Though, Sorata feels awkward because it implies familiarity. With Sorata being Mashiro's caretaker, Sorata and Mashiro become close and learn about each other. Since Mashiro is unsure of her feelings towards Sorata, she often asks Sorata about how she looks in her kimono or swimwear. When Sorata does not pay attention, Mashiro calls Sorata an idiot.
In times of struggle, Sorata supports Mashiro in her manga work while Mashiro did the same for Sorata in his endeavor with video games. Though, Sorata fails and remarks how hard work does not beat talent. His comments hurt Mashiro's feelings. This causes Mashiro to leave Sakura Hall after painting a portrait of the residents except herself. Sorata shares how much Mashiro inspires him to work hard and that he is jealous of Mashiro. Upon hearing Sorata's confession, Mashiro cries and tells Sorata that she wants to stay by his side. After graduation, Mashiro asks Sorata if he wants to kiss her since she has seen Jin kisses Misaki. With Hikari attacking Sorata, Mashiro kisses Sorata's cheeks and tells him that her kiss is a reservation in the future.
Nanami and Mashiro are close friends. In their first meeting, Nanami receives the wrong impressions of Sorata and Mashiro's relationship. Though, she understands Sorata is taking care of Mashiro and volunteers to take care of Mashiro. Unlike Mashiro who is unsure of her feelings, Nanami notices her feelings for Sorata and Mashiro's feelings for Sorata as well. Despite that both girls have feelings for Sorata, Nanami steps down when Sorata confesses his feelings for Mashiro to stop Mashiro from leaving Sakura Hall. Mashiro cries and apologizes to Nanami for hurting her. Nanami hugs her back and explains that she failed the auditions. She is glad that Mashiro cared for her.
Rita is Mashiro's classmate from England. Both of them are art students. Rita comes over to convince Mashiro to come back to England because she wants Mashiro to focus on painting instead of drawing manga. As Akasaka pointed out, Rita envies Mashiro's talents. Rita is angry that Mashiro forgets the names of her and her classmates at school. Rita and Mashiro hug and make up after Sorata states that Rita is an important person to Mashiro. Rita supports Mashiro's endeavors in manga.
Mashiro and her friends take up Misaki's animation, Nyaboron, and turn into a project for the cultural festival at Suimei University of the Arts High School. Though, Mashiro and the gang have a hard time finishing the task as their ideas become larger. During their production, Rita visits Mashiro and her group from England. After Rita and Mashiro make up, Rita helps Mashiro's group with the show. Their show incorporates Sorata's ideas of getting the audience to interact. After a successful day at the cultural festival, Misaki picks up Mashiro and the gang to find Rita who is leaving for England. At the airport, Mashiro and her group bid Rita farewell. Later, Mashiro shares with Sorata that her chest is pounding hard and states that it might be love much to Sorata's surprise.
Mashiro Shiina is a gifted individual whose paintings are revered by everyone. She possesses excellent memorization ability. She can memorize as if it was a picture. This is demonstrated when she memorize the formulas for her math exam. She aced the exam easily.