By Marc Bojanowski

Morrow. 291 pp. $23.95

Readers making their acquaintance with the narrator of Marc Bojanowski's debut novel could easily mistake him for an Ent, one of the destructive lumbering army of tree creatures from "The Lord of the Rings: The Two Towers." Like those Tolkien creations, he towers over his surroundings. As he puts it in his own idiosyncratic, near-Middle-earth diction, he has traveled far and wide in his youth "imposing my great size on others." And like those aging forest beings, Bojanowski's nameless narrator sings his own vanished, mythic past, when his grandfather used to whisper tales of his heroically brutal native Mexican forebears over the objections of his father, a bookish physician of Spanish descent, and the lamentations of his Mexican mother, who saw her brother hideously disfigured by a snake he had taken on in combat.

Yet the grandfather's vision of a primal, beast-smiting Mexico is what drives the boy -- especially since the old man promises that he, too, harbors a mythic destiny. "Your blood is the blood of the men in these stories," the grandfather assures him. "This is a secret you and I share alone. Follow these men from the corners of your dreams and you will be in the dreams of other boys to come."

He is, in other words, an Ent springing from a bad seed. The boy takes his grandfather's words grimly to heart -- so much so that he stops speaking altogether after the old man dies and embarks on a gruesomely successful campaign to outrage his mother, now pregnant with a second child, literally to death. He channels his grandfather's bloodthirsty spirit with a violent rampage through the animal world: He hangs a puppy, detonates field mice and drowns kittens. And his mother beats him until the strain is so apparent that "I no more needed to pray for the child in her to die because I knew she was doing it herself."

His mission fulfilled, the boy abandons his father to grief and madness and travels north to California to work as a farm laborer in the World War II Bracero Program. An affair with a married woman drives him to kill her husband, but since the victim is also Mexican, and hence a legal nonentity, he is merely deported to his native Veracruz. Following the demand for manual labor, he travels to Baja to work on a construction crew for a new hotel, and in the port town of Cancion he discovers his true vocation: the local tradition of dogfighting. But the sport there does not pit two dogs in fights to the death. It pits humans, armed with a defensive swatch of a rug around one arm and a metal claw device on the other, against cruelly trained dogs sometimes with teeth filed to lethal points.

Yet as this mythic creature finds his mythic calling, events around Cancion are luring him into human-scale passions and moral dilemmas. And it's here that Bojanowski's stark, outlandish hero acquires a sympathetic character and the fable of his origins takes on real narrative force. For Cancion is very much a postwar Eden-in-transition: The hotel under construction is slated to transform the poor and pastoral beach town into a resort for rich Americans. Just as the dogfighter graduates from crane operator to local legend in the dog pits, an underground campaign of fires and sabotage overtakes the construction site.

To complicate matters, the hotel developer -- a disreputable, singularly creepy local strongman named Cantana -- is also an impresario of the dogfights, and the strong, silent dogfighter contracts a fierce, debilitating passion for the woman who appears to be Cantana's mistress. Meanwhile, "the poet," an older man who makes a meager living composing letters home on behalf of illiterate workers, quietly recruits the dogfighter to the anti-Cantana resistance. In time, the dogfighter is placed into a classic lady-or-tiger dilemma, with dogs standing in for the tiger.

The plot of the novel is something less than startling in originality, and the prose, while striving for mythic grandeur, often produces comically ungrammatical thuds. Like many writers aspiring to tough-guy minimalism, Bojanowski mistakes herky-jerky bursts of sentence fragments for the authentic speech of working folk, as in "You act like some young fool in love. The poet said but I was quiet." Dangling clauses are an especially irritating weakness; e.g., "I pulled Eduardo by the hair away from a man lying on the ground that he was kicking in the face" and "the poet rolled cigarettes with papers I had bought him while studying the old women dressed in black."

Despite such frequent missteps, it's impossible to lose patience with the story. In part, this is because Bojanowski does a good job stripping the novel down to the most basic what-happens-next level of plotting. But mainly, "The Dog Fighter" makes for an auspicious debut because, beyond the language gimmicks, Bojanowski vividly conjures the voice of a strong, confused soul straining against desires and limitations he only half comprehends. For all his bravado, Bojanowski's narrator gradually comes to realize that he is failing at the things that matter most in life: a reasonable approximation of love and some workable compound of right conduct and self-respect. "I feel that the world is forgiving me each day," the narrator reflects. "Each day another bead on the rosary I do not say." This mood of mingled grace and despair keeps "The Dog Fighter," for all its flaws, in the literary company of other distinguished fighting novels, such as Leonard Gardner's "Fat City" and Stanley Elkin's "Boswell." After all, as legions of Tolkien fans will attest, it is no small thing to bring an Ent down to human size.