They first came across each other at school as Ritsuka was heading to his nap spot. However, the nap spot was already taken by Mafuyu who was already asleep. Mafuyu slowly woke up and sat straight with the two looking at each other without saying a word. Mafuyu then moved over to the side and offered a seat. After exchanging a few words, Ritsuka noticed Mafuyu's broken guitar and asked Mafuyu to get it fixed. Learning that it could be, Mafuyu asked Ritsuka to repair the strings before asking him to teach him guitar.
He admires and joins Ritsuka in a band with Akihiko and Haruki. Ritsuka may be Mafuyu's new potential boyfriend, as he was shown to care a lot about Mafuyu and even going as far as giving Mafuyu a kiss for his efforts after a live performance.
The drummer in Ritsuka's band, Mafuyu is polite towards him as a new person met.
Mafuyu is very amicable towards Haruki, letting him check his hands for blisters and being the first person he gave contact details to then informing Haruki he had a job interview. Acts of casual friendliness extend to sharing indoor barbeque food with Haruki.
When the topic of relationships came up Mafuyu opened up to Haruki talking in-depth on whether he had someone close and what would he do if they suddenly disappeared from the world.
Mafuyu and Yuki met and became childhood friends. The first time they met, Mafuyu was sitting up against a tree by himself. Yuki came by and tried starting a conversation but Mafuyu remained silent for a short while. Mafuyu then decided to inform Yuki that Mafuyu's father would hit him if he spoke. Yuki and Mafuyu both ended up in a household with single mums.
They both started filling up lacking parts in each other and despite their huge differences, they began to give out the vibe that they were made for each other. They both went to the same middle school where they started dating despite Yuki's dominant and moody person and Mafuyu's introvert person, they got along very well.
When they entered high school, they started playing music where Mafuyu played guitar. Mafuyu and Yuki only fought a bit. They would lose their tempers and exchange very harsh words. They both disappeared two days after a fight. One of the following nights, Mafuyu found Yuki's lifeless body and while holding on tight to Yuki's guitar, he breaks one of the strings.
Mafuyu began having a dream that referred to him finding Yuki after his suicide and is very affected by what happened. He clings to the guitar that Yuki once held and rarely leaves it.
He takes a liking towards Ryuu by playing basketball with the other students and is a compliment to his basketball skills.
He sparks an interest in Ugestu during a live performance.
Mafuyu seems to care a lot about Kedama since his mother got him for his birthday. He keeps photos of him on his phone.