In A Doll's House, the drama surrounds Nora and her "secret." Dr Rank seems somewhat unimportant to the progress or development of the plot and, sadly, he is unable to form real relationships with any of the characters although Nora considers him their "best friend" who "never lets a day pass without looking in." He seems to realise that he is " in the way here too" when Torvald and Nora are busy but still persists. He is frowned upon because he flirts with Nora but as she has never even realized it, he seems harmless and is pitied more than judged by any audience.
Dr Rank does not know Krogstad but is quick to form an opinion of him as "a moral incurable." Rank is unwell and Nora is concerned for him but rather dismissive of his illness, refusing to accept that he may die soon. At one point Nora is about to involve him in her problem when he declares his feelings for her and she is somewhat irritated with him that now she cannot share her problem - her secret - with him as it would not be proper, knowing how he feels about her. Nora is very fond of him, such as she loved her "papa."
Nora enjoys his company because he is her friend and it is probably the only adult conversations she can have as Torvald treats her like a child and a "featherbrain." Rank lets Nora and Torvald know he is close to death by sending them a letter but in all the confusion they only see it too late. "He and his sufferings and his loneliness formed a sort of cloudy background to the sunshine of our happiness" is Nora's comment when she learns the news. She will realise too late that her own "cloudy background" will destroy what relationship se has with Torvald and her own family as she feels compelled to leave after her secret is revealed.