Nezuko Kamado is a demon and Tanjiro Kamado's younger sister, as well as one of the two remaining members of the Kamado family. Muzan Kibutsuji attacked her and turned her into a demon when she was a human.
Nezuko has been a fan-favorite character since the show’s debut. She is kind, compassionate, super-powerful, and cute as a button.
After a Demon attack kills almost her entire family, Nezuko is transformed into a Demon by the attack's mastermind, Muzan Kibutsuji.
She is wild at first, even attacking her single remaining brother, but she quickly comes to her senses and leaps in to defend Taniro from Giyu Tomioka.
The siblings then travel together. Tanjiro becomes a Demon Slayer to find a cure for Nezuko and defeat Muzan. During their journey, they cross paths with Zenitsu and Inosuke, fellow Demon Slayers who end up becoming their companions.
Let's discuss who is Nezuko-Chan’s love interest in Demon Slayer.
Zenitsu Agatsuma (Anime)
During the Tsuzumi Mansion arc, Tanjiro asks Zenitsu to protect the box Nezuko is in, without telling him what’s in the box. Zenitsu is deathly scared of demons and happens to have a very sharp sense of sounds.
He could sense there was a demon in the box but protected it at the cost of major injuries anyway to keep his word.
Zenitsu falls in love with Nezuko at first sight when he first sees her despite his fear of demons. She did not appear to reciprocate his feelings at first and remained mostly aloof about his antics.
Zenitsu treats her with affection and care, despite the fact that the two are rarely seen interacting together. Despite his cowardice, Zenitsu musters the courage to ascend to Natagumo Mountain when he realizes Tanjiro and Nezuko are in Spider Family territory, intending to protect Nezuko.
Zenitsu Agatsuma (Manga)
Spoilers for the Demon Slayer Manga. Zenitsu would sit beside her box during their recovery training and tell her stories about Tanjiro and their rehabilitation training.
Nezuko would frequently respond by shaking and scratching her box, implying that she enjoyed hearing Zenitsu's stories.
As Nezuko returns to humanity, she begins to recall her time as a Demon, particularly memory of Zenitsu gifting her flowers, implying that she views him favorably.
Although she was initially concerned by Zenitsu's declaration of her as his wife, the two, along with Inosuke and Tanjiro, would eventually come to live together, marry, and form a family that would yield great-grandchildren in the present day.