JM Coetzee is a consistently self-effacing writer, Joyceanly present everywhere in his work yet nowhere visible. All the same, he has a recurring alter ego through whom he speaks when he is at his most passionate. It is typical of this author that he should choose for his spokesperson – although that is far too strong a word – a woman. When we first met her, in 1990’s Age of Iron, she was called Elizabeth Curren, and, again typically, she was dying. That novel remains one of Coetzee’s finest achievements.

In The Lives of Animals (1999), a pair of lectures delivered in fictional form, Elizabeth Curren has become the ageing novelist Elizabeth Costello, who is much concerned with the “enterprise of degradation, cruelty and killing” of animals, which to her “rivals anything that the Third Reich was capable of”. The abuse of non-human animals is a constantly recurring theme in Coetzee’s work, one that obviously causes him as much anguish and outrage as it does his fictional avatar.

In the 2003 novel Elizabeth Costello, Coetzee effectively killed her off and sent her to a Kafkaesque afterworld. Over the years since then he has resurrected her in a series of enigmatic short stories. Those stories are collected in The Pole, preceded by the eponymous 150-page novella.

The female character here is a middle-aged Spaniard living in Barcelona. Beatriz, “the elegant woman with the gliding walk, the banker’s wife who occupies her days in good works”, is as unlike Elizabeth Costello as could be, and yet somehow we recognise her, so much so that when we come to the following stories and re-encounter Costello herself, the transition is so smooth as to be nonexistent.

The plot of the novella is simple, and as strange as simple things always are. A famous Polish pianist, Witold Walczykiewicz, visits Barcelona at the invitation of a cultural circle of which Beatriz is a member. He will give a concert of Chopin’s music, in which he specialises, though his “somewhatover-intellectualised” interpretation of the Polish master’s delicate pieces is not to everyone’s taste.

He is 72, tall and still vigorous, with a shock of white hair and a striking profile. Often he is mistaken for the Swedish actor Max von Sydow, “my bad brother”, as he says, showing “the ghost of a smile”. Here, the reader will inevitably flip to the author’s photograph at the back of the book jacket, finding there another, more pertinent resemblance. Coetzee, for all his gravitas, is as gamesome as the next novelist.

Witold falls in love, or something like it, with Beatriz. At first she resists, but eventually gives in, and the two end up in bed together. Given Witold’s years, the result is less than earth-shaking. Nevertheless, the poor chap falls in love, totally, and, as it will turn out, for the last time. He even writes a book of poems, endearingly inept, for which Beatriz is the inspiration.

And Beatriz, what is her feeling for her elderly swain? “If she had to pin it down, she would call it pity. He fell in love with her and she took pity on him and out of pity gave him his desire.” Yet it’s not all one-sided; afterwards she remembers the master pianist’s “fingers playing on her skin, drawing music out of her”. And at the end we find her writing fond and melancholy letters to him.

Coetzee the purist has always written close to degree zero; the prose in The Pole is glacial, though we sense swift torrents flowing deep under the ice. The novella is set out in numbered sections, it is not clear to what purpose, and the tone of the dialogue is as wintry as the narrative passages.

There will be no striving after-effects, and nothing of the merely picturesque. Here are Beatriz and Witold out for a walk: “It is a pleasant autumn day. The leaves are turning, et cetera.” You may depend on the likes of Humbert Humbert for a fancy prose style – Coetzee will have none of it. He has stated: “Seriousness is, for a certain kind of artist, an imperative uniting the aesthetic and the ethical.” The project is admirable, and has produced some of the finest novels of our time. Yet in this frictionless world, sometimes transparency can become opacity.

The five stories appended to the novella were written over the past two decades. A couple of them – The Dog in particular – are superficial, and if not, they hide their profundity with cunning and skill. The strongest piece is The Glass Abattoir, in which Elizabeth Costello returns to a proposition she previously put forward, “that people tolerate the slaughter of animals only because they get to see none of it”.

Elizabeth, and her creator, will not relent in their insistence on the seriousness of this matter. They know, as Nietzsche knew, that we are the animal that has gone mad, slaughtering our fellow creatures without a thought or a care. The lives of animals, Elizabeth tells her son – whose name is John, by the way – are “so brief, so easily forgotten … That is why I wrote about them, and why I wanted you to read about them.” And, by extension, about us, too, the butchers, lost in our arrogance, ignorance and uninterruptible self-regard.

• The Pole and Other Stories by JM Coetzee is published by Harvill Secker (£20) in the UK, and Text Publishing (AU$34.99) in Australia. To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply.