Nanachi/Relationships

Bondrewd
When Nanachi first met Bondrewd they were fascinated by his vision and decided, like many other children, to follow him to the Idofront. After the incident with Mitty they started to feel a mix of fear and hate towards him and escaped with Mitty, after having worked as his assistant in experiments for some time.

During the Idofront incident, with Reg and Riko, Nanachi came to terms with Bondrewd's unusual way to view the world and was ready to leave their trauma behind after Bondrewd told them his new dream was for Nanachi to have a fullfilling adventure.

Belafu
Nanachi offered themself to Belafu in exchange for the copy of Mitty he possessed. It's currently not clear how they feel about one another, but Belafu doesn't seem to treat Nanachi badly; as seen when Riko visits Belafu's house.

Mitty
Mitty was the only one of the other children to approach Nanachi, the others complaining that they smelled bad. Mitty was impressed with Nanachi's artistic skills and knowledge, and asked to pair up. Nanachi was reluctant at first, but Mitty insisted, and her gentle enthusiasm quickly won Nanachi over. The two grew very close, and were practically inseparable. One possible interpretation is that Nanachi may have even had romantic feelings towards Mitty, as Nanachi would blush at Mitty's compliments or when they were in close quarters, and would draw pictures of her absentmindedly. The two often held hands, hugged, slept side by side, and were generally very intimate with one another.

During Bondrewd's experiment, just before the two ascended from the 6th layer, Mitty's last words were a tearful proclamation that she wished for her soul to accompany Nanachi if she did not survive. Mitty did survive, but was left in a permanently unrecognizable state — transformed forever into a Narehate, and cursed with immortality. After seeing Bondrewd's relentless torture of Mitty's new Narehate form, Nanachi escaped Idofront with Mitty and vowed to free Mitty's soul from her current physical state. Until that day, their hideout in the 4th Layer was filled with all sorts of books, homemade plushies, and pillows and blankets, all with the goal of enriching Mitty's life. Nanachi treated her as if she was still a self-aware being, and would talk and read books to her. Despite their peaceful living, Nanachi felt that Mitty was their only reason to be alive, and had planned to take their own life after her death was accomplished. Nanachi felt very strongly about this mindset, going so far as to call Reg cruel when he made them promise not to.

When the day came, Nanachi set up a large nest full of pillows and other items they had made for Mitty, so that she could be in comfort even as she was being released. Nanachi said their goodbyes, telling Mitty they would meet again. Only a minute later they recanted this, saying instead they would always be together. When the deed was done, Nanachi fell to their knees and cried intensely, proclaiming Mitty to be their "treasure".

Nanachi copes with their loss by telling themself that they will one day meet Mitty again, though they stated that they don't really believe this will happen. Even so, Nanachi holds onto hope with belief that everything returns to the Abyss, and has even been preparing for their fated meeting by learning how to cook good food.

Reg
Nanachi first encounters Reg when he was attempting to save the life of Riko - who had undergone the strain of the fourth layer and also was poisoned with Orb Piercer venom after they straying into its territory. At first both of them tended to be reluctant to show their feelings several times, but since then have become close friends and value each other as trusted comrades.

Nanachi doesn't like being touched by him, saying the way he does it is "too lewd".

Riko
When Riko woke up, after the poison incident, she quickly became friends with Nanachi. They both enjoy each others company and, unlike Reg, Nanachi allows Riko to touch them; though also not very willingly. Riko named Nanachi the "brain" of the group, due to their vast knowldge and strategically skills.