He looked flamboyantly insane, like some mad doctor from gothic fiction who’d performed too many experiments on himself. And it was his evident madness, I think—and that we all knew him to be capable of true evil—that stopped us from rushing to tear him apart. A man like Caul was never as defenseless as he seemed.

Jacob's narration, Library of Souls

Jack "Caul" Bentham is one of Miss Peregrine's brothers, and the primary antagonist of the series.


According to the third novel Library of Souls, Jack 'Caul' Bentham is siblings with Miss Peregrine and Myron Bentham. Born male, he did not inherit the time controlling ability Miss Peregrine has. Jealous of his sister's power and privileges, Caul would bully his infant sister just for the fun of it and grew up to hate and despise her and ymbrynes in general. As he grew, he became obsessed with the legends of Abaton and the Library of Souls which supposedly houses the souls and abilities of deceased peculiars. Rallying misguided and dissatisfied peculiar youths, most of whom are male, he started a political movement meant to overthrow the ymbrynes as the rightful leaders of peculiardom, promising to lead the peculiars to enslave humanity and rule the world like how it was eons ago when peculiar giants were the dominant creatures. In reality, however, Caul only wanted to install himself as the leader of peculiardom and reshape the world in his image, with his followers being nothing more than cannon fodder and his brother Myron imprisoned when the latter started to question his motives. When Myron realised how dangerous Caul had become, he purposely spread rumors on how to manipulate loops into granting permanent longevity when it was, in fact, an 'arcane and largely forgotten procedure to collapse loops, quickly and permanently, in an emergency'. Falling for the trap, Caul and his followers performed the infamous and controversial experiment in a Siberia loop, which ended devastatingly and turned them into hollowgasts. At some time before the setting of Miss Peregrine's Home for Peculiar Children, Caul managed to feed on enough peculiars and evolved into a wight. He began leading his former followers once more to destroy the ymbrynes and gain access to the Library of Souls, this time with guns to replace the powers his wights had lost. He sent the wight Golan and the latter's hollowgast Malthus to eliminate the famed hollowgast-slayer Abraham Portman and kidnap Miss Peregrine and Miss Avocet, thus laying the setting for the first novel.

Miss Peregrine's Home for Peculiar Children

Caul first appears in his bird form nearing the end of the first novel, stuck in a floating birdcage in the sea. He was released there by the wights in a U-boat after they managed to capture Miss Avocet and the real Miss Peregrine in order to keep tabs on the peculiar children. He was soon 'rescued' by Emma and tagged along with the children in her canoe away from Cairnholm under the identity of Miss Peregrine.

Hollow City


Still spying on the unaware peculiar children, Caul remained in his peregrine form through the journey to Miss Wren's London loop while faking his inability to transform back into 'human' form. In this installment, Caul plays the passive role of monitoring the children's progress without directly aiding or sabotaging their escape from the wights. Uncharacteristically of Ms Peregrine, he killed Winnifred the pigeon in the St. Paul's Cathedral loop, and it is unknown if he wanted to fake Miss Peregrine losing her humanity, silence the pigeon before its nervous behavior roused suspicion or just wanted to kill it. His identity is revealed at the end of the novel when he transformed back into a wight in Miss Wren's hideout of his own will, revealing to the peculiars and ymbryne that he had been stalking them all the while, even capturing the Menagerie and placing the ice fort under siege with his wights. He then initiated a scuffle and tried to take Althea as a hostage, only to stab her with an icicle when she tried to freeze him. With her dead, the ice began to melt away, allowing Caul's wights to storm the fort, capturing all the peculiars and Miss Wren. He then brought his captives to modern day London before escorting them back to his hideout, the Devil's Acre, thus ending the second novel.

Library of Souls

Having brought his captives to the Devil's Acre, he managed to threaten the ymbrynes to unlock the door to Abaton, only to realize he needed a special peculiar, a Librarian, to see and manipulate soul jars to grant Caul its abilities. Anticipating Jacob and Emma's plans to rescue the rest of the peculiars and ymbrynes, Caul set a trap to injure, if not incapacitate them with a swarm of hollowgasts, only for Jacob to control all of them to turn the tide against the wights. Apparently defeated, Caul managed to escape and convince an exasperated Myron to capture Miss Peregrine with his grimbear, taking advantage of an ash storm. Taking Miss Peregrine hostage, Caul entered the Library of Souls where soul jars of ancient peculiars are stored. After having Jacob to empty a soul jar into the spirit pool, Caul shot him in the chest so no one else, especially his brother, could gain power from other soul jars, leaving him as the only peculiar giant alive. Unknown to him, Myron ingested the peculiar soul of Abraham Portman, also a Librarian, and absorbed the soul of another great ancient peculiar while Caul was busy trying to have his revenge against his sister, Miss Peregrine. In the ensuing battle between Caul and Myron, the ymbrynes attempted to collapse the Abaton loop while Caul was distracted, resulting in the loop closing with Caul (and Myron) still stuck inside, leaving him presumably trapped forever, if not dead.

A Map of Days

Caul appears in Jacob's nightmare telling him that he has "big, big plans" for him.

The Conference of the Birds

Caul appears several times throughout the novel via dreams, and on one occassion, through a corpse. He is resurrected by a group of liberated wights since they have nearly all the items to pull him out: an immortal fire stolen from a child's stomach (the Sparkstone), the skull of a long dead peculiar (the Alphaskull from the Well of Hope/Hopewell loop), the tongue of a seedsprout (coming from a mind controlled Fiona whose tongue Murnau ordered sliced out.), one long white worm from one who controls the earth (from Ellery, a girl from an American peculiar clan), death beetles of the Underground Hittites, and finally, the heart from the Mother of Storms (coming from V).

The Desolations of Devil's Acre

Graphic Novels

In the first graphic novel, Caul takes the form of a peregrine falcon and tricks Emma and Jake into rescuing him.

For most of the Hollow City graphic novel, Caul is impersonating his sister, doing cruel things that she never would do, like killing the peculiar pigeon Winnifred. Miss Wren later has him change back into his true form, when he breaks the news about his men visiting the menagerie. When Althea brings him the pants he requested, he takes hold of her hair and threatens to drive an icicle "into her jugular". When she escapes and starts freezing him, he takes a hold of the dropped icicle and kills her. He then has the peculiar children and Miss Wren taken by his wights.



Human form

Nearing the end of Hollow City, Caul is described as 'a stunted little man with knobby knees and a balding head and a nose like a used pencil eraser' right after his transformation from a peregrine into a wight.

Like other wights, Caul looks like an ordinary human with pure white eyes. However, he has a 'weird pair of knobby protrusions' near his shoulder blades, a telltale sign that he can shape-shift into a bird. Otherwise, he does not appear to be much different from any other wight. In his peregrine form, he looks exactly like Miss Peregrine in bird form, complete with black peregrine eyes.

In a picture in chapter four of Library of Souls, Caul was shown to have hair before he turned into a wight, while he was described to be balding in Hollow City (as mentioned above). This could mean that while wights and hollowgasts are essentially immortal, they could still lose their hair naturally, especially when they were balding when the Experiment took place. Note that the picture of Caul and Myron was taken before their relationship soured, perhaps years or even decades before the Experiment took place. Caul's physical condition may have worsened by then, enough for him to start balding.

After Consuming A Soul Jar

Described by Jacob in Library of Souls, Caul became enormous after absorbing a soul, doubling in height and breadth in just a few seconds. He is "a tower of raw pink flesh and tattered clothes," and his eyes become blue. His hands have ten fingers each and are like gnarled tree roots.

In The Desolations of Devil's Acre, Emmerick Dalton (an escapee from Caul's assault on Miss Plover's loop) tells the ymbrynes that the Caul's top half looks like a man, but his bottom half resembles a tree, with roots going into the ground for legs. However, they were made of rotted meat instead of wood.


Like most villains Caul is emotionless, megalomaniac and sadistic, showing emotions only when it benefits him. Myron Bentham claims that the little humanity he had left seemed to dissapear when he became a Wight. Despite the many loyal followers he has, Caul only cares for himself as shown in the end of library of souls when he betrayed his own brother.  Caul is quite sexist as well. He believes that a man should be ruling peculiardom rather than women. He also directly disregards Emma when she is speaking, calling her a "girl" who shouldn't chime in while he and Jacob, who he refers to as "the males", were conversing. 


Although a wight, Caul does have a peculiarity: shape-shifting. Being the brother of Miss Peregrine, he shares the same ability to turn into a peregrine without the aid of ambrosia or external spells. Due to his gender, however, he is not a true ymbryne and cannot manipulate time to maintain loops. However, his shape-shifting peculiarity proves useful in allowing him to deceive the peculiar children into thinking he was Miss Peregrine, thus gaining knowledge of the whereabouts of the Menagerie and Miss Wren's loop in London.

After Consuming Numerous Soul Jars

After Caul was resurrected, he consumed many soul jars, turning him into one of the most powerful peculiars to ever exist. In this state, Caul gained many abilities, one of which was a withering power which would allow him to instantaneously kill normals, and to wither and rot all life around him (including metallic objects which would rust and flake away). Prolonged physical contact with another peculiar would also result in their subsequent death, although it would take a longer period of time to occur. In this form, Caul could not truly be killed (unless all of his soul was devoured by a light eater, such as Noor Pradesh) and every time his physical form was destroyed, he would reform soon after, larger and stronger than before. This got to a point where Caul was absolutely gigantic, at more than fifteen feet in height, and he used his colossal size to his advantage.

In addition to his massive size, he was able to alter his body in drastic ways, such as causing his fingers to become grotesquely long- long enough even to wrap around Myron Bentham's house multiple times. Whilst he was attacking Myron’s house, Caul also displayed the ability to cause an atmosphere of anxiety and despair within the house. Caul could also summon Desolations, violent storms which would precipitate strange objects such as shards of bones, blood, ash and larynxes.

In the event of danger, Caul was also able to fly, easily escaping from conflict. Another aerial ability Caul possessed would be his dominion over wind, as demonstrated when he tossed Noor and Jacob around the Library Of Souls using great gusts of it. Like Jacob, Caul also had control over his evolved hollowgasts, though not the utter control that Jacob displayed. A similar ability Caul obtained was the power to telepathically speak to people from great distances, and give them nightmares, as he did to Jacob when he was trapped in the collapsed Abaton loop. Another notable ability Caul possessed was when he gave the peculiars of Devil’s Acre mental illusions and hallucinations, as well as making a large mental projection of himself to scare the inhabitants of said loop. It is likely Caul had gained even more powers, though they were never shown in the book.

At first, he was not able to cross water, but he later evolved to overcome this. One of Caul’s only other weaknesses was that, if a light eating peculiar went to the source of his power in Abaton, though extremely difficult, they could devour his entire soul and kill him.


Myron Bentham

Caul sees his older brother as lesser than him despite being close in young adulthood. Caul has frequently harmed his brother including breaking his legs beyond repair. When it came to taking on powerful peculiar souls together, Caul said that Myron was too weak to do so, but admits Myron is more intelligent. When Myron begs him, this only seems to confirm Caul's point. In the end, the brothers fight to their death in Abaton. 

Alma LeFay Peregrine

Caul has been physically violent with his sister since childhood including pinching her as a baby and plucking out her feathers in bird form. He believes that she thinks herself superior to everyone else and hates the influence ymbrynes have. As adults, Caul takes great joy in tormenting Miss Peregrine and her wards. He claims that his lack of experimenting on her compared to the other ymbrynes was due to wanting to save the best for last. He shows no remorse in threatening her life repeatedly or causing her physical and emotional harm such as flinging her against a wall or shooting Jacob in front of her. As Abaton collapses, he screams her name in anger. 


  • In his peregrine falcon form, Caul is the only wight to have eyes with black pupils.
  • He is also the only wight to retain his peculiarity. This might be due to bird shape-shifting being a special ability, capable of resisting the effects of the experiment.
  • Despite the experiment, Caul is able to regain his memory after being turned into a wight, reinstating himself as the leader.
  • Caul became one of the most powerful peculiars to ever exist after devouring numerous souls in Abaton, the Library of Souls.
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