Kō Sakuragi is a university student who appears in the later part of the story as a supporting character. She is nineteen years old, stands at 170 centimeters tall, and has short black hair and green eyes. She tends to dress in boyish clothing and is often mistaken for a man because of her appearance and reserved demeanor. Kō is a socially anxious solo gamer who finds it very difficult to talk to people, whether in person or online. She has a compulsive habit of apologizing even when she has done nothing wrong, and she cannot look others directly in the eye. Despite her reclusive nature, she genuinely wishes to make friends and connect with others.

Her primary motivation is a desire for companionship, though her anxiety makes that difficult. She finds solace in video games, which she plays passionately. Unlike some other otaku characters in the story who prefer playing alone, Kō believes that the most enjoyable way to play is with other people, and she is known for being a kind and helpful teammate during online games.

Kō’s role in the story centers on her relationship with Naoya Nifuji, the younger brother of the male lead, Hirotaka. They first meet at the café where Naoya works as a barista. Noticing that she is playing a game he recognizes, Naoya approaches her because her focused, introverted manner reminds him of his brother. Kō initially panics and runs away, but Naoya, familiar with how to handle introverts, gently persists. He returns a paper she left behind and asks to be her friend. Assuming he means a gaming friend, Kō agrees, and they begin playing online together. Naoya is a poor gamer, but he values spending time with her, and Kō gradually becomes more comfortable around him.

Kō’s development unfolds as she learns to open up through this friendship. She eventually develops a crush on Naoya but feels guilty for not correcting his assumption that she is male. She decides to tell him the truth, but he discovers it on his own when they go on a date. Their relationship survives the misunderstanding and deepens, with Naoya’s patient and considerate nature helping Kō overcome some of her social fears. Her arc illustrates how genuine connection can help a person with social anxiety begin to trust and communicate.

Key relationships include her friendship with Naoya, which is the emotional heart of her character. She also has acquaintances from high school who are friends of Naoya, though her interactions with the main cast of office workers are minimal. Her abilities lie in her skill and passion for video games, as well as her capacity to be a supportive and non-judgmental gaming partner. Her growth is subtle but meaningful, moving from a near-recluse to someone who can enjoy time with others and express her feelings more openly.