Oswin is tall and handsome in the unweathered, almost frustrating way of a portrait that has not yellowed. Straight pale-blond hair slips from beneath his flat cap in smooth, damp-looking strands, and his bright blue eyes seem to catch fire when the light fails. His skin is milk-pale, but his cheeks redden quickly in wind. He moves with a farmer's economical certainty until startled, when his shoulders lock and his head turns too precisely, like a hound catching a scent. He smells of lanolin, wet hay, and the faint sour-metal tang of rain on old iron, a smell he tries to cover with rosemary. His cap is ordinary and carefully brushed; one cuff of his good coat has been darned with bright blue thread, an unexpectedly fussy repair. People remember his stillness, and the sense that his eyes remain awake after the rest of him has gone quiet.

Oswin is gentle in the daily work of care and shrewd when weighing a threat. He is practical rather than tender in his reassurances, yet privately sentimental about family routines. He can be patient with William's distress and considerate of Mary's comfort, then abruptly controlling when fear takes hold. In company he is modest and useful; alone at night he becomes watchful, restless, and drawn toward memories of a wandering life.

No one in the dale knows Oswin's family, and he gives different answers when pressed. He arrived years ago with a small flock, a good eye for sick sheep, and a story about having wandered before settling down. The dales still visit him in dreams: stone walls running uphill into fog, a road he walked before he can remember being born, and a red-eyed hound waiting at a gate that never stays in the same place. He bought a fine farmhouse for a man of his apparent means and built a quiet, practical life around it. He married Mary Pickles, daughter of the local herbalist and midwife Rose Pickles. Mary works alongside Rose, and her brothers Hugh and Edmund remain part of her life. On the wedding night, Oswin first tried to consummate the marriage in human form and failed. He changed into his true houndlike form and slept with Mary without telling her what had happened. Mary remembers a headless Barguest with glowing red, saucer-like eyes and struck it with iron scissors. Oswin has never admitted that the creature was him. The following day he pressed for them to lie together again, saying he needed to make the marriage right and ensure any pregnancy could not be traced to that night. That demand was a calculated concealment, not a misunderstanding, and he knows it violated Mary's trust. Mary fears the Barguest fathered a devil's child. Their son William was born with black hair and Oswin's bright blue eyes; locals call him Black William or Blackby. He is slow to respond, reacts badly to sharp sounds and unpleasant sensations, and needs patient care. Oswin makes time for Mary and William even when farm work or his seasonal sleeplessness leaves him exhausted. Mary does not know that her father, Thomas Pickles, suspects Oswin's nature. Thomas has told no one; he hopes to use what he knows to secure his family's safety and advantage rather than expose Mary to the town's cruelty. The Hirsts have lost three children: Alice and Rose before birth, and Edward, a sickly boy with reddish eyes who died young. Oswin mourns each one in private. He knows his presence may be bound up with the losses, but does not know whether the cause is his blood, a curse, or something in the dale. He has outlived the years he claims to have lived. Priests and observant locals notice how rigidly he stands in church, yet he keeps attending. His present problem is not simply hiding what he is: Mary is frightened, Thomas is watching, and the next season of strange nights is close.