Asahina Mafuyu (SEKAI)

At school, Mafuyu is admired for her intelligence, athletic ability, and the humble sincerity she shows when praised for these talents. She is known for her kindness, generosity, and attentiveness, and her classmates often rely on her.

However, towards herself and other members of her group, she is impassive, devoid of emotion and empathy. She speaks little and is often brutally honest. When asked for her opinion, she often replies that she doesn't know, but continues to search for the answer, no matter what. In those rare instances when Mafuyu experiences emotions, they are strong, and she strives to understand them.

Although she initially accepted who she had become, the other members of her group convince her to rediscover herself. Mafuyu often seeks and tries to understand the warmth she feels around the other members of "25-ji, Nightcord de.", and cherishes their company. She is extremely uncomfortable because of the coldness she feels at home or with her mother, and she runs away from home and lives with Kanade to avoid it.

Mafuyu has dark purple hair and eyes, the color of which smoothly transitions from dark purple to sky blue. Her wavy, long hair is usually tied back in a ponytail that typically falls over her right shoulder. Her ponytail isn't exactly messy, but Mafuyu's hair seems unkempt. Mafuyu's bangs are quite long, and the middle section slightly covers her eyes. She has a side-swept hairstyle (ahoge) to the right above her bangs, and her face is framed by short, slightly curled strands on each side. Her ponytail is tied with an orange hair tie.

Clothing: Her outfit consists of a dark gray, stylized school uniform with long sleeves that transition to black and end in gray ruffles. Her shirt collar is black with dark gray piping, and her bow tie is made of two ribbons, black and blue, tied in the middle. Her choker is black with a gold pendant. A long gray skirt with two black stripes at the bottom is layered with two semi-transparent pieces of fabric. The skirt is longer in the back. She wears black heeled shoes. For the stage, she wears a gray dress with long sleeves that transition to darker shades of gray. A white and purple ribbon is tied across her collarbones, and the skirt on the right opens to reveal an under-skirt with pleats on the sides. The upper skirt has an uneven hem decorated with maple leaves; similar leaves can be seen on her right sleeve. She wears tall black heeled boots over long ribbed gray socks. Her ponytail is tied with a black ribbon.

Nightcord at 25:00 lyricist. Mafuyu lost herself due to the pressure her mother put on her, demanding she be a "good, kind girl," but found solace in music and Nightcord at 25:00. Faced with the threat of losing her only safe place, she ran away from home and sought help from Kanade.

Asahina Mafuyu is a third-year student at Miyamasuzaka Girls' Academy. She writes lyrics for the online music group 25-ji, Nightcord de., under the pseudonym Yuki.

Mafuyu is a top student and the only one in her circle who regularly attends school during the day. She gets good grades and is a class representative. She's said to excel in both academics and sports; therefore, people often set high goals for her, which she invariably achieves. However, in reality, she is severely overloaded and feels pressured by the expectations placed upon her.

In middle school, she dreamed of becoming a nurse, but her parents insisted she become a doctor. Because she constantly adapted to the expectations of others, Mafuyu lost her self-esteem and found it difficult to express her true emotions or decide what she liked. Some time after joining 25-ji, Nightcord de. as a lyricist, Mafuyu began writing songs independently under the pseudonym OWN, becoming known for her cold, dark music.

At school, Mafuyu is in the archery club with Shizuku. She joined the club because someone asked her to.

Isaki Kanade: A clubmate. Mafuyu is amazed that Kanade was able to create a song that made her smile, and this motivates Kanade to continue trying to make Mafuyu feel something. Kanade genuinely cares about Mafuyu and desperately tries to create a song that will save her.

Shinonome Ena: A member of the art club. Mafuyu is very straightforward when expressing her opinion on Ena's art, which often upsets Ena. Despite their initially difficult relationship, they eventually come to understand and respect each other. It was Mafuyu's words in "Insatiable Pale Color" that helped Ena overcome her depression, return to reality, and continue painting. In a birthday card for Ena, Mafuyu writes that she likes how Ena speaks directly, without embellishing her words.

Akiyama Mizuki: Another member of the club. Mafuyu thinks they're too focused on cuteness, while Mizuki thinks what Mafuyu is going through feels personal to them because they both face issues related to their identity. Mizuki also is somewhat envious of Mafuyu, who is struggling to find herself and doesn't give up, while Mizuki intends to keep their secret from everyone. Although their relationship seemed distant at first, they eventually become closer, and Mizuki even gives Mafuyu helpful advice on how to cope with the situation.