Mafuyu Asahina, alias "Yuki", is the lyricist for N25. In real life, Mafuyu is an honor student, being her class representative and earning straight-A's. Due to her skill in both academics and sports, people often set high expectations of her to be perfect in order to be "good enough." She tries not to show the effect of the pressure of those around her, instead conforming to what they want. Yet, she is burning out, and she disappears into the Empty sekai for a while after remarking her desire to "give up." Due to her people-pleasing instincts, she has forgotten everything she used to enjoy, and lost her sense of self-identity. She also has trouble recognising her own emotions because of this, but she finds in the N25 main story that her true feelings are finding herself again. She wears a mask of humility and sincerity to those she isn't close with, including her parents, and she is known for being polite and soft-spoken. However, to the other members of N25, she drops this mask, instead being dispassionate, largely lacking in emotion and empathy, being much colder. Her voice is very versatile and her tone fluctuates between different people to show this change in demeanour.