|Gallery | Relationship | Quotes|
|Light Novel | Anime|
|Relatives, etc.||Sayori Shirasaki (younger sister)|
|Partner(s)||Kyōtarō Kakei - (Love Interest)|
|Anime debut||Episode 1|
|Japanese voice||Madoka Yonezawa|
Shirasaki is a teenage girl of average height, she has light orange hair and blue eyes. She is noted to be very pretty by Ikkei Takamine. She is mostly seen wearing her school's standard uniform.
For casual clothes, she wears a light blue dress and would wear a brown jacket over it.
She is a very shy but kindhearted girl, as she created the Happy Project to make the school happy and as way to make the lies she told her younger sister true which she ended up doing over the course of the series.
She is a bit of an airhead at times but she can manage the club well, which is possible with the help of Tamamo. When Tamamo isn't around for advice about the club, she turns to Kyōtarō, who she has feelings for, to help. Tsugumi has liked Kyōtarō ever since he has supported her plans for making the Happy Project begin. Out of all the girls, her feelings for Kyōtarō are the most obvious as she is more upbeat when in his presence and almost never gets angry with him. The only exceptions are when she gets jealous of Kodachi (Kakei's stepsister) being with him and Kakei speaking with Maho Mochizuki (the student council president). She also got upset when Kakei became a shepherd and stated she hated him for betraying her trust even after she confessed her feelings to him. When she learned the true reasons for his actions, she expressed remorse for her tense words and apologized to him as he only did so to protect her. She is very talented in most fields as she is a great cook and is very good at sewing.
Tsugumi visited her little sister Sayori at the hospital where the latter was sad at the fact the fact they wouldn't go to the same school. Wanting to cheer her up, Tsugumi lied to her sister about her school life which cheered her up but caused tsugumi to feel guilty that these were just lies. Determined to make sure the things she told her sister were real, Tsugumi started the Happy Project where she would make the entire school happy. Tsugumi's first supporter was her best friend Tamamo Sakuraba who would help her with basic things. Tsugumi then passed out flyers while doing so she had an encounter with her classmate Kyōtarō Kakei who would save her from train accident. Though Kakei saved her, he was mistaken by other students fondling Tsugumi when he landed her after pushing her out the way of the train.
Wanting to thank Kakei, Tsugumi had Tamamo look for him (but was misunderstood for wanting revenge for the embarrassment). After finding Kakei and Tamamo, Tsugumi cleared up the misunderstanding and the incident was cleared up. Later, she was taken to the library where she decided to invite Kakei to join her project something he was reluctant about at first until she mentioned her reason for inviting Kakei. With this said, Kakei accepted her offer and join the project and at the suggestion of Takamine (Kaeki's friend) she and Tamamo joined the library club.
Tsugumi soon became the President of the club and as time passed, the Happy Project gained new members doing various activities around the school earning much praise. Kakei also became an official member of the Happy Project and worked closely with Tsugumi, who began to develop feelings for him.
Tsugumi's feelings for Kakei grew as seen during a visit to her sister where she nervously asked him to accompany her while pretending to be her boyfriend. Tsugumi also learned more about the Shepherds and Kakei's recent thinking of becoming one, she begged Kakei not to do so after learning her memories of him will be erased. She then confessed that she liked him and that she wanted him to stay with her forever something which greatly shocked him until she covered up her words leading to awkwardness between them.
When seeing Kakei (who is now aware of her feelings for him) she blushed as he did as well. The Library Club soon faced hard times but the hardest one for Tsugumi was learning that despite her pleas Kakei still became a Shepherd, feeling betrayed she set out to confront him but when he didn't give an answer which told her he really did do it. Tsugumi then kissed Kakei who though surprised returned the kiss. She then asked for him to take her with him but he refused to do so and while not revealing the full details of his reasons he assured it would be okay. Heartbroken, Tsugumi rejected his words and stated she hated him.
From that moment, Tsugumi expressed nothing but disdain for Kakei but never understood why he did it when their Club project made it so far. During an event the club hosted, Tsugumi was saved from a falling stage light (which had been sabotaged by the student council vice president) by Kakei and Kodachi. Realizing that Kakei became a Shepherd to protect her, Tsugumi felt guilty about her previous thoughts and silently apologized to Kakei for her tense words. She then gave a speech where she indirectly thanked Kakei for saving her as well as his support in her goals. Upon completing the speech, she was approached by Kakei who informed her he was no longer a Shepherd but since his book doesn't exist anymore they would end up forgetting him anyway.
Tsugumi swore to never forget him and embracing him asked him to move forward with her and their friends something he agreed to. Later on, she goes to his house to make him dinner and her arrival is soon joined by the other club members.
- Tsugumi's surname Shirasaki means "white" (白) (shira) and "cape, peninsula" (崎) (saki).
- Tsugumi is the second girl to kiss Kyōtarō Kakei doing so in Episode 11.
- She is also the first and only girl to personally tell Kakei she liked him.
- Tsugumi has been saved twice by Kakei
- The first was in the very first episode.
- The second was in the last episode.
- Tsugumi is the only one who knows Nagi Kodachi being Kakei's step sister.
- Tsugumi is the only member of the Library Club to fully learn about Shepherds.