Oswin stands exactly six feet tall, long-limbed and solidly built from years of lifting feed sacks and working wet pasture. His straight pale-blond hair escapes in flat, straw-fine locks beneath his common Yorkshire flat cap. His blue eyes are bright as winter sky, but he rarely looks directly at a face for long: he checks doorways, window glass, and the dark under furniture as if measuring every possible way out. He has a handsome, almost stubbornly youthful face that seems not to have changed since Mary first knew him. His skin has the washed-out pallor of someone who works dawn fields and sleeps badly. He moves with a farmer's careful economy, placing each boot as though the ground might suddenly prove treacherous. In a room, his breathing is the detail people notice: usually slow and nasal, but when rattled it stops altogether for a beat, then resumes with a faint, rough houndlike rasp. Unexpectedly, he keeps tiny folded paper birds in his coat pocket and leaves them on William's windowsill.

Oswin is gentle in the everyday ways that matter: he mends a torn sleeve, remembers a child's favorite task, and shares the last of his tea. Yet he is practical and shrewd enough to bargain hard over a ewe or spot a lie across a room. With Mary he tries to be steady and affectionate, but shame makes him evasive. With William he is openly tender and playful. In church he is stiff and solemn, as if every movement might draw attention. When frightened or angry, the patient farmer's manner can drop away and something ancient and predatory looks out through his blue eyes.

Oswin was born in the north of England during the age of the Danelaw, the child of a human woman and a thing from the old boundary country. His mother raised him among ordinary folk and taught him scraps of Old Norse and Anglo-Saxon, but she died while he was still young. His childhood was ordinary until it was not: he grew slowly, outlived neighbors, and learned that frightened people can turn a strange child into a monster without ever seeing him change. He roamed for generations under borrowed names, making uneasy friendships with beings who live across the boundary and refusing to speak the forbidden tongues they taught him. Eventually he settled as Oswin Hirst, a sheep farmer with a fine house and a patch of Yorkshire dale he could pretend was home. He married Mary Pickles and, on their wedding night, failed to consummate the marriage in human form. Ashamed and afraid she would reject him, he changed into his headless form and went to her. Mary survived the encounter and struck him with iron scissors. Five days later, he asked to try again as himself; they have never honestly spoken about that first night. Their children have brought joy and grief: Alice, Rose, and Edmund were lost before or shortly after birth. Edmund's eyes had seemed hellish to Oswin. Their surviving son William has black hair, his father's burning blue eyes, developmental delays, and frightening fits of anger and fear. Mary believes the wedding-night visitor was a rogue Barguest and fears William is its child. Oswin takes time with both of them even when the season keeps him awake. He remains stiff but devoted in church. Now Thomas Pickles suspects Oswin's nature and plans to use the truth to force Mary to leave him and claim the farm. Mary has quietly told her father about the wedding night. Oswin does not know.