Hayashi is the in-game avatar of the protagonist, Moriko Morioka, within the fictional MMORPG Fruits de Mer. Created by Moriko after she quit her draining corporate job and withdrew from conventional society, Hayashi represents a fresh start and a new identity in the online world. She designed him to be the epitome of an eloquent and handsome young man, complete with silky hair, as a sharp contrast to her own real-life appearance as a self-described unemployed and unkempt NEET. However, because he is piloted by the low-confidence Moriko, his demeanor often carries a hint of wimpiness rather than the cool strength his creator envisioned. His character class in the game is a Knight.

Personality-wise, Hayashi serves as a vessel for Moriko's repressed social confidence. Through him, she is able to interact with others in a way her real-world anxiety prevents, presenting a more outgoing and capable version of herself. At the start of the story, Hayashi is a complete newbie to Fruits de Mer, having returned to gaming after a long break, leading to frequent and embarrassing deaths in the early stages of play. Despite this, he is characterized by a genuine kindness and a desire to be a good friend, particularly to the player who first helps him, Lily. He is also prone to the same social awkwardness that plagues his real-world counterpart, often leading to moments of panic, such as when he lies about his offline identity, claiming to be a 21-year-old university student to avoid the shame of revealing his true NEET status. A core part of his personality is his thoughtfulness, as seen in his secret plan to grind levels for a difficult quest to obtain a rare in-game item, a crystal rose, as a Christmas present for Lily, despite the immense effort it would require.

Hayashi's primary motivation is the pursuit of a fulfilling human connection, something Moriko found lacking in her real life. Because she is terrified of being judged, the online world provides a safe haven, and Hayashi is the persona through which she seeks companionship, adventure, and meaning. He is deeply invested in his friendships within the game, especially his growing bond with Lily. The fear of losing this connection or of being rejected if his true identity is discovered is a constant driving force behind his actions and anxieties.

Within the story, Hayashi acts as the crucial link between Moriko's isolated real life and her vibrant online existence. Nearly all of the narrative's central conflicts and romantic developments stem from the dual identity he represents. His relationship with the player Lily is the emotional core of the series. What begins as a mentor-mentee dynamic, with the experienced Lily teaching the novice Hayashi the ropes, quickly deepens into a close partnership within their guild, @HomeParty. Unbeknownst to Moriko, Lily is actually controlled by Yuta Sakurai, a handsome elite salaryman she has met in real life. This creates a complex love square of sorts, as Moriko develops feelings for Sakurai in reality and for Lily in the game, not realizing they are the same person. It is through the interactions and advice he receives as Hayashi that Moriko finds the courage to take steps forward in her real-world relationships.

Key relationships for Hayashi extend beyond just Lily. He is a member of the @HomeParty guild, which provides a supportive community. The guild leader, Kanbe, acts as a source of wise and cautious advice, once warning Hayashi not to get too attached to players outside the game. Fellow guild members Himeralda and Lilac also serve as confidants, offering enthusiastic, if sometimes misguided, romantic advice when Hayashi recounts his real-life troubles in a gender-swapped story. These guildmates provide the social feedback loop that Moriko lacks in her daily life, propelling the plot forward.

Hayashi undergoes significant development alongside his player, Moriko. Initially a symbol of her escape from reality, he gradually becomes the catalyst for her re-engagement with it. As Hayashi's relationship with Lily deepens, Moriko is forced to confront the walls she has built around herself. Her initial lie about her age and student status weighs on her, representing the guilt of maintaining a false persona. However, the genuine care she receives as Hayashi helps build her self-esteem. The ultimate narrative development is the merging of these two identities. The story does not end with Hayashi being abandoned for reality, but rather with the realization that the person Moriko is online and the person she is offline are one and the same, and the love she found as Hayashi can be translated into a real-world connection with Yuta Sakurai.

In terms of notable abilities, as a player-character, Hayashi's primary skills are those of a Knight in the game, which include combat proficiency and the ability to protect allies. While not an elite player initially, he is dedicated and willing to work hard, such as through dedicated level grinding to overcome challenging quests. His most significant ability, however, is not a game mechanic but a narrative one: his existence as a highly effective emotional shield. The avatar of Hayashi allows the socially petrified Moriko to speak, make friends, and express affection in ways she cannot manage as herself, making him the primary instrument of her personal growth throughout the story.