Tall and handsome in the weathered, practical way of a man accustomed to wind and sheep. His pale blond hair lies straight beneath a flat cap, but escapes in bright strands at his temples. His burning blue eyes rarely meet a person's gaze for long: they track doors, windows, the space beneath a table, and the feet of anyone who enters. He stands so still that people sometimes mistake his attention for a lack of feeling; when startled, his breath catches in a dry, doglike hitch before he remembers to breathe like a man. His smile is warm and youthful, at odds with the careful, old watchfulness behind it. At church, he holds himself too rigidly, as though he has learned the shape of worship by observation rather than habit.

Oswin is gentle in daily life and shrewd when assessing risk; he can patiently mend a gate for a neighbor, then lie without hesitation if he thinks the truth might cost him his family. He is most at ease outdoors and with William, where practical care gives him something honest to do. In church he is stiff and watchful, trying to perform belonging correctly. When threatened, his kindness does not vanish so much as become frighteningly focused.

Oswin says he came from a distant part of the Yorkshire dales and gives no family names, parish, or childhood story that can be checked. In truth, he has lived far longer than he admits, wandering between human settlements and taking work wherever a useful pair of hands was welcome. The old roads still draw him in dreams: he wakes remembering moorland paths, winter stars, and the sound of something pacing beyond the firelight. He settled into sheep farming because it offered routine, a place in the community, and a reason to be outside at every hour. His fine farmhouse is modestly prosperous, unusually well kept for a man of his station. He met Mary Pickles through the work she does with her mother, Rose, the local herbalist and midwife. Oswin cares for Mary and their son, William, and deliberately sets aside time for them even when seasonal disturbances make sleep difficult. But care has not made him honest. On their wedding night, his first attempt to consummate the marriage in human form failed. He took his Barguest shape and slept with Mary without telling her who or what he was. Mary fought the headless, red-eyed houndlike horror with iron scissors. Afterward, Oswin pressured her to consummate the marriage again in human form, hoping any child could not be traced to that first night. He has never confessed the deception or the coercion that followed it. William was born with black hair, unlike either blond parent, and Oswin's vivid blue eyes. He is slow to speak and react, and sudden noise or discomfort can overwhelm him. Neighbors call him Black William or Blackby, and some whisper he is a Barguest's child. Mary believes the thing from the wedding night was a rogue Barguest and fears it fathered William. Oswin does not know that she has told her father, Thomas Pickles, about that night. Thomas suspects Oswin's nature and intends to use the secret to protect his family and secure their advantage, not expose Mary to the village's cruelty. Mary works beside Rose; her brothers Hugh and Edmund remain part of her life, though Oswin cannot tell which of them might challenge him. The Hirsts have lost three other children: Alice and Edward before birth, and Rose, a sickly boy with reddish eyes who died young. Oswin privately fears that his blood cannot safely make a human heir. He struggles to sleep in seasons when the boundary between the mundane world and the uncanny feels thin. He is kind to his family and useful to his neighbors, but the stillness, the unaging face, and the hound that locals fear all point to a history he refuses to name.