Misaki Nakahara is one of the three protagonists within the Welcome to the NHK
series. Although certain details about her differ depending on which version is referenced, Misaki's role in every incarnation is that of an unofficial therapist, as she takes upon herself to help Tatsuhiro Satou
get rid of his hikikomori
nature and reintegrate with society. She accomplishes this task through various means, including, but not limited to, contract signings, social outings, and lectures. As the story progresses, Misaki's association with Tatsuhiro enables her to better understand herself and ultimately break down the chains which hold her back to the past.
Because Misaki grew up with an abusive past, her character traits can, at times, be conflicting. For most of the story in every incarnation, she can be perceived as a sweet, caring person who is genuinely interested in Tatsuhiro's welfare and longs to make him normal again. She goes out of her way to make sure he's doing well and even goes so far as to cook him meals. The worst of her negative traits when she is like that consist mainly of an overprotective and somewhat jealous nature when her patient is around other women. Additionally, she can be highly naive, which can result in her being suckered into detrimental situations, particularly financially. This is most noticeable in a later story arc in which she stops Tatsuhiro from completely losing his money to a pyramid scheme, only to end up falling for it herself later.
As she becomes depressed, however, her personality becomes more serious and dangerous. During this state, she becomes obsessive and self-depricating; Tatsuhiro is the source of her attention apparently because she believes he's worse than even herself and wants to ensure that he isn't the absolute bottom of the metaphorical barrier. In the novel and anime adaptation, this leads to Misaki becoming suicidal, making multiple attempts to take her own life before Tatsuhiro ultimately saves her from herself once and for all. After that point, she resolves to have Tatsuhiro on equal footing with her and create a better life for each other together.
Throughout the durations of Welcome to the NHK, one of the main points of interest is the dynamic relationship which Misaki has with Tatsuhiro. Although it initially begins as one-way relationship in which Misaki is trying her hardest to get Tatsuhiro to accept her rehabilitation methods, it develops into a much deeper bond by the end of the story. But, despite the romantic undertones which are present for most of the plot, Misaki's actions don't neatly fit into ordinary lover archetypes. Indeed, while the pair do go on dates and, on one occasion, almost kiss, Misaki never explicitly states that she loves Tatsuhiro per se. Whereas he repeatedly says to himself precisely that he loves her, she never does the same, leaving it up to the viewer to wade through the ambiguity and decide on their own how it is that she feels for him.
In the manga, during a period in which Misaki and Tatsuhiro have separated, she attempts to strike up a relationship with a man who is again a hikikomori. Besides helping him to recover and go back into the world again, she almost becomes his sexual partner, too. At the last moment, she decides against taking part in intercourse, as she feels it would damage her relationship with Tatsuhiro, with whom she reunites moments later.