- Caulker's Mate on Terror, Cornelius Hickey is a young petty officer whose rank on the ships should, by any standard, keep him invisible to the officers. But Hickey is not quite what he seems. With streetwise intelligence and intense social ambition, he attempts to ingratiate and triangulate his way up the social ladder. But when his early efforts fail, a newfound contempt for authority leads him to an even more dangerous agenda, threatening the expedition from within even as the men battle terrifying forces from without.
In the series
Hickey is first seen in episode 1 heading down into the lower deck of Terror and having a drink then eating with the ship's boys, Thomas Evans, David Young, Robert Golding and Able Seaman William Strong, criticizing the officers and the dog Neptune, until Young takes ill and later dies. The next day he helps bury Young and after his coffin lid comes off in his grave, Hickey climbs in to replace it despite Sergeant Tozer's protest, ostensibly out of respect, but in reality to rob the corpse. Later when Erebus and Terror get stuck in the ice, he is seen along with the others trying to pick their way out of it. (Go for Broke).
Months later in episode 2, Lieutenant John Irving catches Hickey after a tryst with William Gibson. Gibson is worried Irving will report what he saw but Hickey assures Gibson he won't. Later, whilst caulking Crozier's cabin, the ship's dog Neptune fouls the carpet and Hickey cleans it up; when Crozier suddenly enters. Hickey initially apologizes as this is not one of his duties, but Crozier compliments him on taking initiative and offers him a drink (Gore).
During episode 3, Hickey overhears Gibson tell Irving that he was forced into the relationship by Hickey, resulting in Irving lecturing Hickey. He takes his revenge during Sir John Franklin's funeral, which he leaves early to foul Gibson's bed. Whilst doing so he goes through Crozier's desk and finds a letter of resignation (The Ladder).
In episode 4, Hickey finds the bodies of William Strong and Thomas Evans on Terrors deck. He figures out that Lady Silence is connected to the Tuunbaq and takes the initiative to kidnap her, accompanied by Magnus Manson, Thomas Armitage, Thomas "Tom" Hartnell, and implicitly aided by Tozer. Whilst approaching her, he sees her with the Tuunbaq which flees before the party, staring back at Hickey. When the officers discover what has happened, Crozier orders Hickey, Manson, and Hartnell to be flogged for abandoning their posts without orders while Armitage remains undiscovered. Hickey's punishment is increased to 30 lashes and receive them on the buttocks after he argues with Crozier. After his lashing, he is treated by Doctor McDonald, and afterwards finds that someone, perhaps Tozer, has left tobacco in his hammock (Punished, as a Boy).
In episode 5, Hickey gives Gibson the ring he stole from Young in order to gain information about the officers. He tries to get onto the deck when the Tuunbaq attacks the ship, but the hatch is blocked (First Shot a Winner, Lads).
During episode 6, Hickey learns from Gibson that the officers are starting to take inventory of empty storage items and begins to suspect they may abandon ship soon. Later, Hickey leaves the carnival to relieve himself and is therefore not inside when Doctor Stanley sets it on fire. He uses his knife to cut an opening in the main tent allowing most of the crew to escape, but in the process he also accidentally stabs and kills Doctor McDonald (A Mercy).
A few months later during episode 7 when both ships are eventually abandoned, Hickey listens to Gibson's idea about splitting off from the main group to form their own smaller, faster group, and Hickey believes there will be others who also like the idea. By watching Doctor Goodsir and Lady Silence not eating the tinned food and witnessing the suicide of John Morfin, he learns there is something wrong with the canned foods. Hickey later kills the ship's dog, Neptune, which he claims fell on some rocks and broke its leg. He and Tozer use the food and the knowledge of Crozier's intention to resign to get Lieutenant George Henry Hodgson to join a mutiny they are planning. Hodgson, Hickey, Irving, Armitage, Thomas Farr, and Francis Pocock later lead an expedition to find food. After Irving finds a friendly Inuit family who feed him, which would ruin the plans for mutiny, Hickey stabs Farr and Irving to death (Horrible from Supper).
In the next episode after killing Farr and Irving, Hickey tells the rest of the party the Inuit killed them, resulting in the family being massacred. When he returns to the camp he spreads rumors about the Inuit, fomenting some chaos, and plans to put the mutiny into action with Gibson. The officers force Hickey to return to the spot where Irving was killed, and after an autopsy, they realize that Hickey must have killed him; Hickey and Tozer are sentenced to be hanged. Hickey reveals Crozier's former intention to resign on the scaffold, but the majority of the crew are still against him, and he only escapes death when the Tuunbaq attacks the camp in retaliation for the Inuit killings. He, Tozer, and the other mutineers escape with a boat, weapons, and supplies (Terror Camp Clear).
Hickey's mutineers include himself, James Daly, Gibson, Tozer, Manson, Golding, Armitage, Charles Des Voeux, John Diggle, Edmund Hoar, William Pilkington, and a reluctant Hodgson. They also capture Goodsir as they escape. In episode 9 when Gibson falls ill with lead poisoning, Hickey stabs him to death and forces Goodsir to prepare the body for the mutineers to eat. Tozer later tells him about what the Tuunbaq did to Collins, and begs him to lead the mutineers out of the area, but he refuses. Tozer, Armitage, and Pilkington begin to plot another mutiny, against Hickey himself (The C, The C, The Open C).
During the final episode, Crozier is captured and brought to Hickey's camp, where Hickey tells him that Crozier is his only equal on the expedition. The mutineers later eat Goodsir's poisoned body, although it is unclear if Hickey consumes him. During the dinner, Hickey knocks out Tozer, having gotten wind of his planned mutiny. He then chains the men he does not trust to the boat and forces them to drag it out onto the wastes, where he reveals to Crozier that he is an impostor who murdered the real Cornelius Hickey and took his place. He then draws the Tuunbaq in by singing. The monster kills or chases off all the mutineers save Hickey, who watches from the boat. He then attempts to perform the shaman ritual carried out by Lady Silence by severing his tongue and offering it to the Tuunbaq, but it rejects him, biting off his arm and tearing him in half. After his death, the Tuunbaq chokes to death on the upper half of his body (We Are Gone).
In the book
Near the end of the novel, Hickey uses Golding to lure in Crozier and Goodsir, then captures them both, murders John Lane and William Goddard, and shoots Crozier four times. Goodsir soon commits suicide after being tortured because he refuses to butcher bodies for Hickey.
In the following days, Hickey shoots half the mutineers to feed the rest, who all die of illness or exposure anyway. By this point Hickey has decided he is not a god, but God himself, so the death of Magnus Manson does not bother him, as Hickey believes can be resurrected. As he is thinking about his godhood, the Tuunbaq appears in the distance. Hickey grows more and more terrified as it moves closer and eventually smashes and eats Manson's corpse, but is frozen in place by the extreme cold. The Tuunbaq moves into Hickey's face and breathes his soul in, but before the monster can devour it, it sneezes in disgust, spits the soul out, and leaves Hickey's body sitting frozen on the gunwhale of the boat, to be eaten by scavengers and buried under the snow.
- A bone-handled table knife inscribed with initials of Cornelius Hickey was obtained from the Inuit at Repulse Bay in 1854 by the Rae Expedition. The Inuit said they had found the material at a camp to the north west of the mouth of the Back River where a party of Europeans had died of starvation.
- Also found at Repulse Bay was a table spoon that belonged to both Lieutenant James Fairholme and Cornelius Hickey.
- Despite being sentenced for 30 lashes, Hickey receives 23 before Crozier allows him to be released.
- Adam Nagaitis was allowed to come up with his own name for the impostor Hickey. His real initials, E. C., are carved into his cupboard, the cubby hole seen in Horrible from Supper.
- The plot point of Hickey being an imposter was a creation of the TV series, likely to avoid libeling the real, historical Cornelius Hickey, who may not have been a cannibal, and probably was not a mutineer or a murderer.
- The series also changes Hickey's partner from Magnus Manson to William Gibson, as the novel character's relationship with the "idiot" and "halfwit" Manson could be construed as non consensual.
- The novel's Hickey is less sympathetic than he is in the series, as he is mutinous from the outset, and lacks the character arc of turning against authority due to his lashing. In an interview, author Dan Simmons said he welcomed the new, more complex Hickey.
- Although Hickey does not attempt to tame the Tuunbaq in the novel, he is one of the first to realize that it is a spirit and not an animal. He and his clique also wear charms of the Tuunbaq, which are eventually banned by Crozier.
- It is never truly explained how Hickey learned the ritual of severing one's tongue to control the Tuunbaq and how Blanky described the Tuunbaq as "a spirit that dresses as an animal" as he did not witness either event. It's likely he heard various bits of information throughout the expedition and was able to put the pieces together.