Nagasaki Sosei

Biodata

Feature	Information
Name	Nagasaki Sosei (长崎素世)
Alias(es)	Sose; Soyo / Soyo-san 30 281
Gender	Female
Affiliation	Moon Forest Girls' Academy; former member of crychic; member of MyGO!!!; Moon Forest wind ensemble club 10 100 274
Occupation/Role	First-year student; musician; MyGO!!! keyboardist and later identified as its bassist 10 100 245
Status	Active 316
First Appearance	Chapter 10 10

Background

Sosei lives alone after moving into an apartment next to Bai Qiu. When she twists her ankle while moving in, Bai Qiu helps carry her luggage; she later thanks him with Wuyi Mountain Black Tea. Their neighborly relationship begins from this encounter. 10

Her parents separated when she was young. Her mother works extensively to provide for her, but frequent absences leave Sosei isolated in their large home. Sosei responds by presenting herself as mature, considerate, and self-sufficient, even when she is deeply lonely. 28 77 310

Following crychic's dissolution and Toyokawa Shoko's disappearance, Sosei becomes increasingly withdrawn. She investigates girls' schools throughout Tokyo, using student lists and her social skills to track Shoko down. 44

Appearance

Sosei cultivates the polished image of a Moon Forest young lady: neat, refined, and warmly approachable. This is a stark contrast to her disheveled first meeting with Bai Qiu while moving in. 10

• Azure-blue eyes. 278
• Flaxen-brown hair. 211 251
• Keeps her school uniform immaculate and wrinkle-free. 10
• Speaks in a soft, sweet voice; when anxious or trying to be persuasive, its carefully gentle quality becomes more pronounced. 30 90

Personality

Sosei is outwardly gracious, hospitable, and attentive to others. She cooks for people close to her, worries about their health, and readily takes on a caring role—particularly with Bai Qiu and Wakaba Mutsuki. 28 89 209

Her gentleness masks a strong fear of abandonment. Heavy rain evokes memories of her parents' separation and Shoko leaving crychic, causing her to withdraw, neglect herself, or become overwhelmed by grief. 77 81 88

She is intensely attached to the people and memories she considers irreplaceable. This drives her prolonged effort to restore crychic and later manifests as jealousy and possessiveness concerning Bai Qiu. Though usually restrained by Moon Forest etiquette, she can become unexpectedly bold and competitive when challenged. 76 138 281 316

Abilities & Skills

Bass

Sosei originally handled the bass part in crychic and is especially familiar with the song “Kasumikage.” She prefers fingerstyle playing over using a pick. 79

• Played crychic's bass parts before the band's dissolution. 79
• Stopped practicing for a significant period after crychic ended; long fingernails and an unfamiliar left-handed bass hinder her attempted return. 79
• Later resumes serious bass practice and improves her playing. 245 301

Keyboard

Sosei joins the newly formed band as its keyboardist despite initially lacking keyboard experience. 99 100

• Requests keyboard instruction from Bai Qiu. 104 153
• Receives additional instruction from Toyokawa Shoko. 153
• Performs “Kasumikage” on keyboard during a live encore. 162

Cooking & Household Care

Sosei is a capable home cook and frequently expresses affection through meals and gifts.

• Cooks for her mother and prepares meals for Bai Qiu. 28 168
• Learns Chinese dishes specifically for Bai Qiu. 209
• Gives Bai Qiu a bouquet of flowers in return for the perfume he gifted her. 209

Investigation & Social Maneuvering

Sosei persistently searches for information on Shoko after crychic disbands.

• Visits girls' schools across Tokyo to check new-student records. 44
• Uses her social polish and small bribes to persuade students to obtain lists for her. 44

Equipment / Personal Items

• Bass — Her original crychic instrument; she is protective of the band's music and memories. 79
• Keyboard — Used for MyGO!!! activities and practice. 153 156
• Perfume from Bai Qiu — Her first significant gift from him; she carries the bottle closely and fears losing it. 168 277

Relationships

• Bai Qiu — Neighbor, musical teacher, and eventual boyfriend. He repeatedly supports Sosei through her grief, while she cares for him through cooking and domestic gestures. Their mutual confession begins their relationship, which her mother later approves. 10 153 277 310
• Toyokawa Shoko — Former crychic bandmate whom Sosei desperately seeks after the band's dissolution. Their relationship is strained by Shoko's refusal to return, but gradually improves through music and renewed contact. 76 153 168
• Wakaba Mutsuki / Mortis — Former crychic bandmate and close friend. Sosei is hurt by Mutsuki's silence during the search for Shoko, but remains concerned for her and later helps care for Mortis. 77 89 268
• Takamatsu Tomo — Mutual friend of Bai Qiu and former crychic bandmate; later performs with Sosei in MyGO!!!. 30 99
• Shiina Rikki — MyGO!!! bandmate. Rikki feels betrayed when Sosei asks Shoko for compositional help, but later apologizes and repairs their working relationship. 143 153
• Chihaya Anon — MyGO!!! bandmate and Bai Qiu's other girlfriend. The two are friendly but openly competitive over their respective places in Bai Qiu's life. 280 281 316
• Nagasaki's Mother — A hardworking but often absent parent. She recognizes Sosei's loneliness, approves of Bai Qiu, and encourages Sosei to pursue her happiness. 28 310

Story Role / Major Arcs

Neighbor and Crychic Search

After meeting Bai Qiu during her move, Sosei learns that he knows Takamatsu Tomo and may have information connected to Shoko. Her efforts to locate Shoko become increasingly single-minded after crychic's collapse. 10 30 44

Confrontation with Shoko

Sosei finally finds Shoko in Shimokitazawa and pleads for her return to crychic. Shoko refuses, calls their former promise a lie, and tells Sosei to look forward; the rejection leaves Sosei devastated. 74 76

Joining MyGO!!!

Rather than remaining alone after crychic, Sosei joins the new band formed around Tomo, Rikki, Anon, and the others. She initially takes the keyboard position and continues learning the instrument. 99 100 153

Reconciliation and “Kasumikage”

Sosei's attempt to recruit Shoko as a composer causes conflict with Rikki, exposing how strongly Sosei still clings to crychic. After the former members communicate more openly, her obsession with restoring the old band begins to fade. 131 143 168

During a MyGO!!! performance, Sosei plays “Kasumikage” while seeing Shoko backstage. She feels guilty for occupying Shoko's former keyboard role, but performs alongside the band. 162

Relationship with Bai Qiu

Sosei confesses to Bai Qiu, is gently rejected, and struggles to preserve their friendship. Rather than giving up, she becomes more direct about her feelings. 210 211 223

After witnessing Bai Qiu kiss Anon, Sosei retreats alone to Tokyo Bay in despair. Bai Qiu finds her in the rain, reassures her that he loves her, and accepts her confession. 275 277 278

Sosei later becomes openly recognized as Bai Qiu's girlfriend, while navigating a tense, competitive understanding with Anon and other girls who have feelings for him. 280 281 315 316

Notable Quotes

“I won't give up.” — Nagasaki Sosei 223

“I like Bai Qiu, I like him a lot...” — Nagasaki Sosei 210

“Don't be unhappy if I actually do it later.” — Nagasaki Sosei 315

Trivia

• Sosei strongly dislikes heavy rain because it is tied to memories of her parents' separation and Shoko's departure from crychic. 77 81
• She is one of the few double bass players in Moon Forest's wind ensemble club. 274
• Bai Qiu's perfume was the first carefully prepared gift she had received apart from birthday gifts from her mother. 168
• Her bouquet for Bai Qiu is the first bouquet of flowers he has ever received. 209