Sakayanagi Arisu

Biodata

Feature	Value
Name	Sakayanagi Arisu (坂柳有栖)
Gender	Female
Affiliation	Advanced Nurturing High School; originally Class 1-A, later Class B; Student Council 5 76 443
Occupation/Role	Student; leader of Class B; Student Council member 76 343 443
Family	Only daughter of school chairman Sakayanagi Narimori 282 290
Status	Active second-year student; congenital heart disease cured through treatment provided by Hashiba Hikaru 393 443
First Appearance	Class A’s representative election 5

Background / History

Arisu grew up in an extremely wealthy family with longstanding connections in education. Her father sought treatment for her congenital heart condition at hospitals in several countries, but none offered an effective solution. Exposure to upper-class power struggles also gave her experience with political maneuvering from a young age 377 468.

She became proficient at various board games during childhood, reaching a high level by age ten. She also visited the White Room once when she was very young; that visit gave her familiarity with its existence, but little useful knowledge of its internal layout 201 290 483.

Despite her physical limitations, Arisu entered the school’s original Class A. Her academic and intellectual abilities were strong enough to secure that placement even without athletic ability contributing to her evaluation 67 76.

Appearance

Arisu has a petite frame, short silver hair, fair skin, and purple eyes. Her delicate features are repeatedly compared to those of an elf, while her posture and movements are described as elegant and refined 5 77 135.

• Short stature: Crowds can obstruct her view, prompting her to ask Kamuro Masumi to clear a path 385.
• Cane: Her most recognizable accessory before her recovery; she initially carries a black cane in her right hand 5.
• Off-duty clothing: One outing features a black beret, pale plush coat, fur-collared knit cardigan, ribbon tie, above-knee skirt, white stockings, and black leather shoes 361.
• After treatment: She walks steadily without her cane, visibly surprising classmates and other class representatives 380 381.

Personality

Arisu’s polite speech and faint smiles conceal an aggressive competitive streak. She enjoys disrupting other people’s plans, seeks control of her class, and regards Hashiba Hikaru as an especially suitable opponent to surpass. She is comfortable with solitude and does not treat loneliness as an obstacle to her ambitions 140 232 245.

Her composure does not make her indifferent to losing. Strong opponents ignite her fighting spirit, but she admits defeat decisively rather than making excuses; when outplayed, she considers further practice the appropriate response. Her competitiveness also has a rational side: she cooperates with rivals when a larger threat makes an alliance worthwhile 201 234 345.

Arisu rarely displays her true emotions openly, making her difficult for Hashiba to read. As their relationship develops, she becomes more affectionate, proactive, and possessive. Although she accepts the possibility of an approved partner having multiple relationships, she still shows jealousy toward women competing for his attention 300 439 445 486.

Her attitude toward enemies can be ruthless: she explicitly favors expulsion and supports Hashiba’s decision to remove Hosen Kazuomi even when he questions whether his motives are merely personal bias 341 458.

Abilities & Skills

Chess and Board Games

Arisu’s childhood experience makes her a formidable board-game opponent. She calculates sequences mentally and favors decisive, aggressive attacks 201 400.

• Defeats Hashiba in three consecutive chess games during their initial clubroom matches 201.
• Recognizes his rapid improvement by tracking how many moves she needs to win each successive game 201.
• Defeats a second-year student at shogi and offers to teach Hashiba 141.
• Directs Kamuro’s chess moves through the Commander Tower, turning her average playing ability into a sustained offensive against Ando Sayo 400.
• Is not unbeatable: Hashiba later wins twice consecutively, and she estimates her chances against him at approximately forty percent during the final Special Exam 234 402.

Academic Ability and Mental Calculation

Arisu approaches ordinary examinations with exceptional confidence. Her strengths extend beyond accumulated knowledge to rapid calculation under pressure 67 398.

• Uses her Commander Tower intervention to answer the ninth Rapid Mental Math question, securing Class B’s victory in that event 398.
• Selects written examinations and intellectual contests as central components of her class’s Special Exam strategy 392 393.
• Retains enough spare attention during a demanding chess calculation to continue provoking Ichinose Honami 400.

Leadership and Political Maneuvering

Arisu builds authority through factional support, information control, and carefully timed challenges rather than emphasizing class unity 140 251 443.

• Expands her faction to nearly two-thirds of Class B after Katsuragi Kohei’s consecutive Special Exam failures 140.
• Alters one examination question to expose discrepancies in Class C’s answers and counter accusations against her faction 251.
• Uses a public dinner with Hashiba to signal their alliance to Katsuragi and Ryuen Kakeru 223.
• Calls for concentrated Criticism Votes against Totsuka Yahiko and challenges Katsuragi to initiate a vote of no confidence if he opposes her decision 354 364.
• Serves as a Student Council interviewer; Hashiba later broadens her responsibilities to develop her execution skills 202 203 482.

Intelligence Gathering

Arisu has access to information channels connected to her father and the Sakayanagi family’s educational network 290 468.

• Identifies the White Room’s attempt to frame and suspend the chairman 290.
• Shares reports on suspicious first-year applicants with Hashiba and Ayanokoji Kiyotaka through their group chat 451 456.
• Uses OAA photographs to identify students she has not personally met 440.
• Investigates an unusual meeting between the Kujo family’s heir and the Koenji family’s head 472.
• Supplies first-hand information confirming that the Kujo family has publicly abandoned Ayanokoji Atsuomi 498.

Her access is not omniscient: she initially lacks the White Room’s detailed plans, and her single childhood visit cannot supply a reliable map of its facilities 290 483.

Psychological Warfare

Arisu combines class competition with personal pressure, particularly when confronting Ichinose 381 397.

• Questions whether Ichinose’s class could remain at the top without Hashiba 344 397.
• Proposes a wager involving Hashiba to unsettle Ichinose before their Special Exam confrontation 381.
• Uses provocative remarks between events to test her opponent’s composure 397 398.
• Changes tactics when emotional manipulation fails, resolving to defeat Ichinose through the examination itself 396.

OAA Evaluation

The following panel is displayed while Arisu is in Class B of the Second Year, under the heading “First Year Results” 443.

Category	Grade	Score
Academic Ability	A	93
Physical Ability	D	36
Flexible Thinking	B+	82
Social Contribution	B-	68
Comprehensive Ability	B	70

Her heart condition has been resolved by this point, but further physical training is still needed to improve her score 443.

Health and Recovery

Arisu’s cane use stems from a congenital heart defect, not damaged legs. Strenuous activity places excessive strain on her heart, preventing her from participating in sports. Before treatment, she forfeits Sports Festival events requiring every student to compete 139 377.

Hashiba offers treatment using the Heaven-Sent Medical Kit, and Arisu agrees to trust him. He administers medicine and visits her dormitory daily during the seven-day course to monitor her condition 377 378.

Chapter	Development
379	Near the end of treatment, Hashiba still observes no obvious recovery; Arisu begins considering whether she might eventually participate in physical events.
380	She awakens without the previous pressure on her heart, feels markedly lighter, and walks to class without a cane.
380 393	Her recovery is established, but she stresses that adapting to sports will take time and continues prioritizing intellectual contests.

Equipment / Weapons / Items

• Cane — Mobility aid used to reduce physical strain before treatment. It is described as black at her introduction and gray during her Valentine’s visit; she stops relying on it after recovery 5 343 380.
• Activity Classroom / clubroom — A room she obtains for chess, coffee, private conversations, and strategic meetings. Hashiba never sees its club application among the budgets he normally approves 201 322 393 404.
• Deck of cards — Used to initiate a two-person game of Truth or Dare with Hashiba 361 362.
• Handmade chocolates — Presented to Hashiba as genuine-love chocolates on Valentine’s Day 343 344 345.
• Perfume — She changes fragrances and invites Hashiba to smell the new scent on her wrist 439.
• Ring — Worn on the middle finger of her right hand during a discussion of the Kujo family 470.

Relationships

• Hashiba Hikaru — Rival, strategic partner, and romantic interest. Their relationship develops through chess, political cooperation, a standing handshake agreement, and his treatment of her heart condition. She later confesses her feelings and promises to support him regardless of his actions 201 282 322 377 468.
• Sakayanagi Narimori — Her father and the school chairman. She deeply respects him, gains access to information channels through him, and opposes outside interference in the school 245 282 290.
• Kamuro Masumi — Trusted follower and practical assistant. Kamuro prepares coffee, delivers meals, monitors Hashiba’s relationships, and carries out Arisu’s chess instructions during the Special Exam 322 363 378 400.
• Katsuragi Kohei — Rival for class leadership. Their factions compete for control, and he opposes her handling of examination leaks and the concentrated Criticism Vote against Totsuka 5 251 364.
• Ichinose Honami — Rival class leader and competitor for Hashiba’s affection. Arisu recognizes her leadership qualities but targets her vulnerabilities and directly challenges her in Special Exams 282 316 317 381.
• Ayanokoji Kiyotaka — Ally against the White Room. She coordinates intelligence and countermeasures with him and Hashiba, although her interest in him diminishes after Hashiba becomes her principal intellectual rival 282 290 451.
• Ryuen Kakeru — Rival whose cooperation with Katsuragi threatens her position. She publicizes her alliance with Hashiba partly to send him a warning 215 223 245.
• Kiryuuin Fuuka — Romantic competitor and occasional temporary ally. Their polite exchanges contain pointed verbal sparring, and cooperation can quickly give way to competition over Hashiba’s time 367 410.
• Tsukishiro — Acting chairman and adversary in the White Room conflict. Arisu helps investigate his concealed examination arrangements and plan responses 373 443 444.

Story Role / Major Arcs

Arc	Chapters	Role and developments
Class leadership struggle	5 140 251 282	Ties Katsuragi in the initial representative election, steadily enlarges her faction, counters his examination-leak accusations, and ultimately gains control of Class B.
Student Council cooperation	76 183 199 203	Joins the council, raises the prospect of Class A supporting Hashiba’s vice-presidential candidacy, and works with him on proposals and recruitment. He owes her three favors after securing votes.
White Room alliance	245 282 289 290	Makes cooperation against the White Room her third requested favor. After Hashiba notices a suspicious call, she investigates the pressure on her father and joins a three-person alliance with Hashiba and Ayanokoji.
Ichinose’s past and the rumor incident	316 317 320 322 324	Discovers Ichinose’s past theft and plans to reveal it. When a forum post adds other allegations, she says she knows only about the theft. She later assists Hashiba’s response, making a handshake at every meeting the condition for helping access deleted print records.
Open romantic pursuit	341 344 362 364 366	Declares her Valentine’s chocolate a true-love gift. Hashiba initially refuses because of Ichinose, but their subsequent outings become increasingly affectionate; Arisu calls their meal a date and later initiates a kiss in his dormitory.
First-year final Special Exam	381 398 400 401 402	Challenges Ichinose, wins the Rapid Mental Math event, and gains an advantage in the deciding chess match through Kamuro. Hashiba pays one million Private Points to replace Ichinose as Commander Tower and reverses the match. Arisu admits defeat but continues pursuing him.
Incoming first-years and Tsukishiro’s schemes	413 434 443 444 445 456 458	Helps investigate possible White Room agents, uncover the hidden exam targeting Ayanokoji, and develop countermeasures. She also agrees to support the effort to expel Hosen.
Wider political conflict	468 470 472 482 498	Advises Hashiba on a possible Koenji-family partnership, investigates the Kujo family’s contacts, takes on expanded council duties, and reports the Kujo family’s public break with Ayanokoji Atsuomi.

Love Stock Market Role

Arisu is an investable character in Hashiba’s system. Her stock responds to their rivalry, her interest in his abilities, and their growing intimacy 208 282 366.

Chapter	Documented stock event
208	Hashiba purchases her stock. Its analysis identifies defeating her as a way to raise its price, encouraging him to commit fully to their daily chess matches.
282	Her interest in how Hashiba persuaded Ayanokoji to become his assistant raises the price by 20, reaching 100.
366	The price rises after she initiates a kiss; no numerical value is provided.
443	Hashiba notes that her price has been stuck at 200 and considers whether a special action is needed to increase it further.

Notable Quotes

“Because I prefer to meddle in other people's plans. Fighting against others is the most enjoyable thing there is.” 232

“Please do not worry. Any decision made by Classmate Hashiba is equivalent to my own. If he agrees to your request, then I will agree as well.” 364

“I am willing to trust you.” 377