Please explain who the characters are in A Doll's House.

By focusing only on Nora and Torvald, the first answer
ignores the fact that there are seven characters in the play. Let me list them for you
and give a brief description of each one.

The
Porter: appears in only one scene and doesn't figure in the
action.

The Maid: She has very
few lines and doesn't figure in the
action.

Nora Helmer: The main
character and the person around whom the action revolves. She is married to Torvald, and
she is keeping a secret from him that will eventually ruin their marriage when it is
discovered. She only pretends to be
helpless.

Torvald Helmer:
Nora's husband. He treats Nora like one of the children, constantly
calling her "little squirrel" and "featherhead." He constantly fusses at her for
spending money and eating sweets. He cares very much about appearances and suggests an
unconventional solution to the problem when Nora's secret is
revealed.

Dr. Rank: Torvald's
friend and physician. He is secretly in love with Nora and treats her with more respect
than her own husband does.

Christine Linde:
An old friend of Nora's who is widowed and comes to Nora to ask for help
getting a job. She married for money instead of for love, but she is now penniless
and bitter about it.

Nils
Krogstad: the antagonist of the play. He works for Torvald but knows he
is going to be fired because of mistakes he has made. He has discovered Nora's secret,
and in a desperate attempt to keep his job, he blackmails her into persuading Torvald
not to fire him. He was the love whom Christine left behind, and they are reconciled in
the end.

I hope this helps you.