Before blackmailing Nora, Krogstad takes part in Nora's crime of forgery, and demonstrates that his reason is to save the life of his sick wife who dies later leaving behind her the children under Krogstad's care. Without a job, he would not be able to cover the requirements of those children.
Nils Krogstad is, at least at the beginning, the antagonist of the play. Known to the other characters as unscrupulous and dishonest, he blackmails Nora, who borrowed money from him with a forged signature, after learning that he is being fired from his job at the bank.
Like Nora, Krogstad is a person who has been wronged by society, and both Nora and Krogstad have committed the same crime: forgery of signatures.
Ushering the children out of the room, Nora is alone with Krogstad. He has come, he says, to ask her to intercede with Torvald on his behalf, for only her influence can protect the job which Christine Linde might take from him.
After revealing the information he can use against her, Krogstad flat out threatens Nora. At this point in the play, Krogstad is not only seeking to restore his reputation, but wants revenge if he cannot keep his job at the bank.
Mrs. Linde is explaining to Krogstad why she left him to marry her husband. Even though she loved Krogstad, Mrs. Linde believed she had to marry someone with money so that she could take care of her family.
Krogstad says that Nora has other things to worry about: he has figured out that Nora forged her father's signature on the promissory note. Krogstad informs Nora that her forgery is a serious offense, similar to the one that sullied his reputation in the first place.
After Nora rather easily admits to her forgery, we learn that Krogstad's bad standing in society, the cause of his moral disease, results from committing the same crime. He tells her that “what I once did was nothing more, and nothing worse, and it destroyed me” (Ibsen 166).
What effect does Krogstad's blackmail have on Nora? It breaks her will to achieve independence.
In the play, money symbolizes the power that the characters have over one another. In the first scene, Torvald's ability to dictate how much Nora spends on Christmas presents shows his power over her. Meanwhile, the debt that Nora owes Krogstad allows him to have power over her and Torvald.
If the marriage aim, as alleged by Kristine, is to take care of a disabled mother and younger siblings, then the marriage to her lover (Krogstad) equally fulfills this purpose: with mutual labor, they can sustain the family, albeit in poverty.
Krogstad threatens Nora that he will reveal her past crime of forgery unless she helps him. He remarks that he is prepared to fight for his small position at the bank as if he is fighting for his life. He does not want to lose his reputation, his dignity and his position in society.
Major conflict Nora's struggle with Krogstad, who threatens to tell her husband about her past crime, incites Nora's journey of self-discovery and provides much of the play's dramatic suspense.
Nora is a victim of the male-dominated society of the nineteenth century. To save her husband, Torvald, she borrows money so that he might be able to recover from a life-threatening illness in a warmer climate.
As the play progresses, the audience comes to learn that due to a sickness Torvald had in the past, Nora in order to pay for a trip needed to save Torvald's life was forced to take a loan from a rich man known as Mr. Krogstad.
Torvald's decision to fire Krogstad stems ultimately from the fact that he feels threatened and offended by Krogstad's failure to pay him the proper respect. Torvald is very conscious of other people's perceptions of him and of his standing in the community.
Torvald says he can't stand Krogstad because he does dishonest things like forgery. Nora's husband goes on to say that he can't stand being around such awful people. He talks about how such people's presence corrupts their children. Torvald goes back to work.
At first, Nora's interaction with Dr. Rank is similarly manipulative. When she flirts with him by showing her stockings, it seems that she hopes to entice Dr. Rank and then persuade him to speak to Torvald about keeping Krogstad on at the bank.
In Act 1 of A Doll House, Krogstad tells Nora that “Laws don't inquire into motives” (1342) and Nora responds, “Then they must be very poor laws.” What Krogstad means when he tells Nora this is that no matter how good the intention or motives of a person are, if they break the law it is still illegal.
Krogstad leaves and when Torvald returns, Nora tries to convince him not to fire Krogstad. Torvald refuses to hear her pleas, explaining that Krogstad is a liar and a hypocrite and that years before he had committed a crime: he forged other people's signatures.
What secret has Nora been keeping from Torvald? She was in love with his brother before she married him.
Linde marries her husband for money so that she can support her sick mother and dependent younger brothers.
Bitterly Krogstad reproaches Christine for renouncing their betrothal, years ago, sacrificing him in order to marry a man better able to support her and her family. After wrecking his hopes the first time, she appears again to stand in his way by taking over his hard-won position at the bank.
Rather than marrying the dashing young Nils Krogstad, she married a businessman, Mr. Linde, so that she could support her sick mother and her two younger brothers. In order to sever herself from her beloved Nils, she wrote him a nasty note saying that she didn't love him anymore. (A little harsh, Christine.)
He speaks slightingly of her husband. Why isn't Nora worried about Krogstad? She expects to be able to pay off the debt easily in the new year.