Oswin stands six feet tall, pale as unbleached wool, with straight blond hair that falls to his jaw when he forgets to trim it. His blue eyes are vivid and steady in daylight, but in shadow they seem to hold a cold inner flame. He has the smooth, youthful face Mary remembers from the start of their courtship, untouched by the years that should have changed it. He keeps himself carefully shaved and brushes his hair with almost fussy attention, an incongruous vanity for a working sheep farmer. In a room, his gaze does not linger on faces: it counts doors, windows, iron fittings, and the nearest dark corner before returning to whoever is speaking. He moves with a shepherd's quiet economy, turning his shoulders sideways through crowded spaces as though avoiding an invisible tether. In his true headless shape, the body is dressed as Oswin is, but the head is absent and two red eyes burn in empty air above the collar. As a hound, he is huge, black, and long-legged, with a coat that drinks up lamplight and a chain-rattle that seems to come from nowhere. The first impression he leaves is of a pleasant, handsome young farmer who is listening to something far off.

Oswin is gentle in the practical way of someone who has spent years keeping fragile things alive: he notices a lamb shivering, a child falling behind, or a neighbor carrying more than they can manage. Yet his gentleness is entangled with secrecy. He wants Mary to feel safe, but he withholds the truth that would let her judge her own danger. He can be patient with William's slow progress and impatient with adults who mistake slowness for stupidity. In ordinary company he is dryly humorous and modest about his means; when a threat appears, he becomes abrupt, watchful, and startlingly decisive. He loves the steadiness of farm life while privately longing for the open roads and lonely heights of his wandering years. He is not simply ashamed of being a Barguest. He is ashamed that, when faced with an awkward human failure on his wedding night, he chose the form Mary feared rather than risk an honest conversation.

Oswin Hirst was born in the Yorkshire dales during the Danelaw, the child of a human woman and something the village never had a safe name for. His mother survived a Viking raid, but the years that followed left her frightened of the dark and unwilling to speak of his father. Oswin grew up learning that hunger, weather, and people could all turn suddenly. He was strong, quick to read a room, and difficult to keep in one place. As a young man he wandered the dales and the roads beyond them, sometimes in human shape and sometimes as a black hound. He carried messages, found lost sheep, and once led a band of stranded travelers through a snow-choked pass by scent alone. He remembers those years as a chain of half-true stories: a ruined chapel where a dead priest spoke, a winter funeral at which every dog in the valley followed the bier, and a ford he could not cross though the water barely reached his knees. The formative event came after he had begun to understand that his long life was no ordinary blessing. A village healer named Heddah, who had sheltered him as a boy, was accused of witchcraft after a child fell ill. Oswin tried to defend her as a man, but the frightened crowd drove him off with iron tools. He returned as the hound and scattered them, yet arrived too late to save her. Her final words were not a curse. She told him that being feared was not the same as being evil, and that he must choose what to do with the fear he carried. He has remembered the words, though he has not always lived by them. Long afterward, restless and weary of people who knew his stories but not his habits, Oswin settled into a respectable sheep farmer's life. His fine stone house, healthy flock, and careful accounts have made him seem fortunate rather than uncanny. He met Mary Pickles and loved her patience, practical humor, and refusal to be impressed by his old road tales. He wanted a marriage that did not begin with fear. On their wedding night, however, he failed to consummate the marriage in human form. Ashamed, frightened that Mary would think him weak or strange, and desperate to give her the marriage he thought she expected, he took his headless Barguest shape. Mary experienced the encounter as an assault by a monster and has never known that the creature was Oswin. He has never told her. Her terror has become his private punishment, and he tells himself that disclosure would only hurt her further. Their son William, whom the locals call Black William or Blackby, has unusual black hair despite both parents being blond, and Oswin's burning blue eyes. William is slow to speak and learn compared with other children, but attentive to animals and weather. Oswin gives him time every day, even when seasonal visitations leave him sleepless. Mary believes the child may be the Barguest's spawn. She keeps iron scissors and an iron thimble near him, and watches Oswin closely during seasons associated with the fae. She has not told Oswin that she confided the wedding-night terror to her father, Thomas Pickles. Thomas is suspicious of his son-in-law and has begun to consider how Oswin's secret might benefit the Pickles family. Mary's brothers, Hugh and Edward, are protective in different ways: Hugh wants to confront Oswin, while Edward prefers to gather proof. The Pickles family still grieves Alice, Mary's older sister, who died of a winter fever after Thomas failed to find help in time. That grief has made Thomas more controlling and more willing to mistake leverage for protection. Recently, Oswin touched iron in a moment of panic. A lamb had caught its leg in an iron gate during a storm, and he grabbed the hot hinge to free it before the animal broke its leg. The iron burned him through his palm and left a pale, branching welt that has not healed properly. He hid the injury under a glove and told Mary it was a burn from the hearth. For days afterward he could not shift into a hound, and the helplessness frightened him more than the pain. Now the uncanny seasons are returning. Oswin's sleep breaks into fragments, his old wandering dreams pull him toward the high dales, and he fears that the next appearance of the headless shape will make Mary finally understand the truth, but not in the way he hopes.