The Gentleman with the Thistledown Hair is the primary antagonist in Suzanna Clarke's "Jonathan Strange and Mr. Norrell", an alternate history novel depicting the quest of Jonathan Strange and Gilbert Norrell in returning magic to England during the Napoleonic Wars and the Regency Era.
The Gentleman, who is never named or given a name out of narrative by Clarke, is a Faerie, a mythical being of north European origin. It is revealed throughout the book that the Gentleman is the ruler of several Kingdoms in Faerie (also the name of the land Faeries hail from), although the only one visited in the book is Lost Hope, which principally comprises a brugh (earth barrow) magically imbued to resemble and great mansion, and its surrounding lands.
The Gentleman habitually wears a leaf green coat, and possesses long, silvery hair the shape and texture of thistledown, leading to his enigmatic epithet. He has "pale, perfect" skin, bright blue eyes, and dark, perfectly formed eyebrows that terminate in an upward flourish. His skin is always deathly cold, and his voice is described in various supernatural ways.
The Gentleman controls a vast array of magical powers granted to him through his ability to converse with, and form alliances with the forces of nature. For instance, near the end of the book, he inquires of the sun and the dawn whether they might bring him at once to the person who is the greatest threat to his life. While the Gentleman is proof against most forms of mortal death, able to magically reform himself should he come to harm, he is not indestructible, and sometimes the fear of death can throw him into extreme anxiety, or a lethal rage.
The Gentleman is also able to divine the future through a variety of magical means. Typically these means involve the deaths of numerous people. For example, in the search for the true name of Steven Black, he required planks from a sunken ship, a pearl necklace, a garment, and the magical essence of a kiss. The planks had been taken to make a poor man's house, which the Gentleman burned down and took the ashes, killing the women, elderly, and younger members of the family. In order to procure the necklace, he strangled the French Revolutionary official who owned it, with it while the official was trying it on. The garment had been cut up and made into a counterpane for a bed, which the Gentleman took, leaving the elderly woman in the bed to likely die from cold. The kiss, which had been taken by a man hanged several years prior, had been transferred to all the women the man had kissed since, necessitating the Gentleman to kill each and every one of them to draw enough of the essence together.
He is also described as diving the future by examining the dripping bloody guts of dying men on lonely battlefields.
A fictional author within the story wrote a scholarly work on faeries in where he described that Faeries and men both contain a faculty of reason and a faculty of magic. In men, logic is strong, and magic weak, while magic is a Faery's natural affinity, and by human standings, they are barely sane.
The Gentleman carries this description through to the letter. Although not actually evil, the Gentleman frequently shows a blunt disregard for the thoughts, feelings, or well being of others while being overly sensitive himself, and has so little a grasp on the social conventions of human beings that he more often than not mistakes innocent actions or misunderstandings as direct, personal insults to himself or his friends. Described as mercurial, his mood can and often does change from one extreme to another within the space of minutes.
The Gentleman has a curious habit of seeing undesirable qualities in other people, while ignoring those same qualities in himself (although it is perfectly possible that he is simply unaware that he possesses these traits as well), and is not above making scornful remarks about perfectly mundane qualities, such as someone's height, the make of their boots, or the way they cut their nibs.
He considers himself a great benefactor to his friends, and during the course of the book, develops an affinity for Steven Black, the negro butler to the English politician, Sir Walter Pole. Steven, who is very handsome, clever, and worldly, impresses the Gentleman, who immediately determines upon enchanting him so that he must take part in his, the Gentleman's, nightly balls at his mansion at Lost Hope. Despite being always very affectionate and friendly to Steven, making him extravagant gifts, such as seals from ancient military orders, gold and silver items aplenty, a statue from a Medici family tomb, a well-bred horse, a golden watch, and many other things, the Gentleman makes Steven extremely unhappy by enchanting him and showing him all sorts of polite attentions, but is simply unable to comprehend that Steven is being miserable.
The Gentleman is first encountered when Mr. Norrell summons him to raise the to-be-wife of Sir Walter Pole, Emma Wintertowne, back from the dead. The Gentleman does so in return for half of Miss Wintertowne's life and interprets this as meaning that he can take her away every night to his mansion at Lost Hope. Mr. Norrell figures out what the Gentleman has done, and berates him, beginning the Gentleman's general animosity towards him, and any other living English magician.
In the course of his getting ready for a ball at his house, he strikes up an acquaintance with Steven Black, the African butler to Sir Walter, and becomes impressed with his cleverness, excellent manners, and handsomeness, all of which he considers the chief qualities in a person. Following this initial meeting, the Gentleman enchants Steven so that he is forced to attend the nightly balls at Lost Hope, leading to Steven to become tired and dejected, and indifferent to his usual life. The Gentleman also shows him constant attentions, and gives him innumerable extravagant gifts, most of which Steven had no use for.
Later on in the story, the Gentleman watches the progress of the magicians, Jonathan Strange and Mr. Norrell, and at one point followed Strange, invisible, to a meeting with King George III, who was mad at the time. Strange, who had gone to try and cure the king, became perplexed when the King spoke to the Gentleman (Strange not being able to see the Faerie), as the King, being mad, could perceive him. The Gentleman, having previously made a prophecy that Steven would be the ruler of "a kingdom where he had already been", decided that Steven must be destined to be King of England, and thus attempted to enchant the King, only to be inadvertently thwarted by Jonathan Strange. Enraged by this, the Gentleman concocts an elaborate plan to kidnap Strange's wife and hold her forever in Lost Hope, weaving a complex illusion to make it seem to her friends and loved ones as though she had died.
Later on, Jonathan Strange manages to summon the Gentleman and perceive him by developing an elixir of madness. The Gentleman, who views the magicians as dangerous to him, tries to shake him off by offering him gifts that would indirectly bring trouble upon Strange, and distract him, but becomes ever deeper worried as Strange unknowingly threatens the Gentleman's control over Emma Wintertowne (now Lady Pole). Strange, believing the Gentleman's reluctance is down to the Gentleman not believing in the merits of his power, travels to Faerie and visits the Gentleman's house, where much to his surprise, finds his wife. The Gentleman, believing the magician had come to destroy him, pleads for Stevens advice, and manages to instantly misinterpret said advice. He subsequently imprisons Strange in an eternal pillar of constant night, freezing time within so that Strange doesn't age, but must live out 100 years of "solitude and darkness".
Later, the Gentleman divines Steven Black's true name through various horrible means. Before he can inform Steven of his name, however, he senses the magicians release Lady Pole from her enchantment and immediately sets off to kill her after killing Vinculus, a street sorcerer the sun and the dawn had told the Gentleman was a great threat to him.
At the same time as this, the magicians are attempting to summon John Uskglass, the legendary Raven King, in order to help them defeat the Gentleman, and unwittingly imbue Steven Black with total control over the natural forces in England. Acting to prevent the Gentleman from killing Lady Pole, he causes various aspects of nature: the stones, a nearby river, and a hill to destroy the Gentleman. The Gentleman attempts to resurrect himself through magic, being unbelievably old and powerful but is eventually killed, buried under a small hill of stones and silt. Steven Black takes his place as King of Lost Hope, thus fulfilling the prophecy the Gentleman had made earlier in the book.