For most of The Promised Neverland, the enemy seems to be the demons who eat the children. The final antagonist is human. Peter Ratri is the 36th head of the Ratri clan, the overseer of the farm system and the guardian of the Promise: the pact sealed a thousand years ago by his ancestor Julius Ratri, under which humans and demons divided the world, and a supply of human children was guaranteed to the demons in exchange for peace. The Ratris have managed that supply ever since. Peter is charismatic, a skilled negotiator, ruthless and narcissistic; he calls himself the father of the children while regarding them, the Sisters and even Isabella as nothing more than food. He became head of the family by betraying his older brother James, who wanted to free the farm children, and executing him as a traitor; later he killed every other member of the clan who had supported James. If criminology wanted a family in which crime is inherited, it could hardly design a better one.
// The theoryCrime in the blood
The theory of criminal heredity took shape in the late nineteenth century, in the same climate as Lombroso's born criminal. In 1877 Richard Dugdale published The Jukes, a study of a New York family with an extraordinary number of criminals, paupers and prostitutes across several generations. Dugdale himself was cautious and gave environment a large role, but his study was read as proof that crime was hereditary. In 1912 Henry Goddard went further with The Kallikak Family, which traced two lines of descendants from one man—one "degenerate", one respectable— and blamed the difference on inherited feeble-mindedness. The family studies became the scientific backbone of the eugenics movement, and of laws that led to the forced sterilisation of tens of thousands of people. Later scholarship showed that the data were deeply flawed, and the field moved on to twin and adoption studies, which find a modest genetic influence on antisocial behavior, always interacting with environment and never amounting to a destiny.
What families actually pass on
The family studies made a basic error: they saw crime running through a family and concluded it was in the blood. But families pass on far more than genes. They pass on property and position, roles and expectations, networks, loyalties and a sense of what is normal. Dugdale half-saw this; his own line about heredity producing an environment that perpetuates it is an admission that the two cannot be separated. The Ratri clan makes the distinction impossible to miss. Nothing in the series suggests the Ratris are biologically different from anyone else. What they inherit is an office: the management of the farms, the wealth it produces, the knowledge of the Promise, and a code that treats any member who questions it as a traitor. Peter did not inherit a violent temperament. He inherited a job, and a family that kills those who refuse it.
// The subjectThe brother who said no
Peter's own history shows that the family tradition was not automatic. His older brother James Ratri, whom Peter adored as a child, came to see the farm system as monstrous and began working in secret to free the children—he is the figure the orphans know as Minerva. Two brothers raised in the same house, with the same blood and the same education, took opposite paths. Peter informed the family elders of James's plans, was chosen as the next head, and executed his brother; he then hunted down and killed every member of the clan who had sided with him. Together with the demon royals, the Ratris also massacred the clan of Mujika, demons whose blood could free their kind from the need to eat humans, because it threatened the farms, the money they produced and the Promise itself. When the demon queen and nobles are finally killed, Peter does not see a chance to free humanity. He sees a chance to take control of the demons and keep raising children as livestock, on his own terms.
Peter Ratri
Get the map of theories for free
Subscribe to the criminal archive —one case a week, no spam— and I'll send you The map of theories: the great currents of criminology on a single sheet.
// The crackIf it were in the blood, James would not exist
The case of the Ratri brothers is the strongest possible refutation of the old theory. Same parents, same blood, same upbringing, and one becomes the guardian of the system while the other dies trying to destroy it. Hereditary determinism has no way to explain James. Modern behavioral genetics would not try to: it says that genes influence probabilities in interaction with environments, and that individuals within the same family differ enormously. What does explain the Ratris is social, not biological: an institution that recruits its heads from one family, rewards loyalty, punishes dissent with death, and makes the family's wealth and identity depend on the crime continuing. That is the structure of many real criminal dynasties, from mafia families to ruling families of regimes built on violence.
The theory's history deserves its own warning. The criminal-family studies did not stay in academic journals: they were used to justify the sterilisation, institutionalization and exclusion of the poor, the disabled and minorities, on the grounds that their crime was in their blood. The irony that The Promised Neverland stages is pointed. The people who were labeled hereditary criminals were usually powerless; the family that really did transmit an atrocity across thirty-six generations sat at the top of the world. Peter chose to betray his brother and to keep the farms running. But if anything was inherited, it was the throne, not the guilt.
Dynasties, not bloodlines
Peter Ratri matters because the question of inherited crime is still with us, and the evidence points somewhere very different from where the old theory looked. Research on intergenerational offending does find that crime runs in families: children of convicted parents are more likely to be convicted themselves. But the mechanisms that explain most of it are social—shared environments, poverty, the labeling and policing of particular families, the imprisonment of parents—and the same research shows that most children of offenders do not offend. At the other end of the social ladder, criminal and corrupt dynasties pass on power, money and impunity, and rarely end up in the family studies at all. The Ratris are fiction. The pattern of a family business in harm, protected by its position, is not.
Three key ideas
- The theory of criminal heredity, from Dugdale's Jukes (1877) to Goddard's Kallikaks (1912), claimed crime traveled in the blood of certain families; its flawed studies underpinned eugenics. Modern twin and adoption research finds only modest genetic influence, always interacting with environment.
- Peter Ratri is the 36th head of a clan that has managed the farms for a thousand years. He inherited an office, a fortune, a pact and a code that kills dissenters: he betrayed and executed his brother James and purged the clan members who supported him.
- The crack: James, with the same blood and upbringing, chose the opposite path, which hereditary determinism cannot explain. What the Ratris transmit is social, and the irony is that the family studies blamed the powerless while dynasties at the top passed on real atrocities.
Sources · further reading
- Dugdale, R. L. (1877). The Jukes: A Study in Crime, Pauperism, Disease and Heredity. G. P. Putnam's Sons.
- Goddard, H. H. (1912). The Kallikak Family: A Study in the Heredity of Feeble-Mindedness. Macmillan.
- Rafter, N. H. (1997). Creating Born Criminals. University of Illinois Press.
- Shirai, K. and Demizu, P. (2016-2020). The Promised Neverland (manga). Shūeisha.
Case-file questionsFrequently asked questions
Who is Peter Ratri?
Peter Ratri is a villain from The Promised Neverland, analysed on KRIMINIS through the lens of criminology. His older brother wanted to free the children of the farms.
Why does Peter Ratri become a villain?
Peter Ratri and the theory of criminal heredity: the final villain of The Promised Neverland is the 36th head of a family that has spent a thousand years guarding the pact that turns children into food. Criminology spent a century looking for crime in the blood of poor families. The Ratris show what is really inherited.
Which criminological theory explains Peter Ratri?
Peter Ratri's case is analysed through Criminal heredity. The theory of criminal heredity held for a century that crime traveled in the blood of certain families. Richard Dugdale's study of the Jukes and Henry Goddard's of the Kallikaks seemed to prove it, and served as an alibi for eugenics. Peter Ratri, the final antagonist of The Promised Neverland, is its perfect irony: a family in which crime really is passed down from generation to generation, for a thousand years, and in which nobody carries bad blood. What is inherited is an office, a fortune, a pact and a duty of loyalty. Exactly what the criminal-family studies mistook for biology.
