Is Aurum Blood real? Discover the true story of the Rh-null “Golden Blood,” the rarest blood type in the world, and its meaning in Netflix’s My Dearest Assassin.
Sometimes, movies and TV series lead us to discover concepts and stories we might otherwise never have encountered. They often appear so otherworldly that our instinct is to dismiss them as mere fictional devices—creative inventions designed solely to drive the plot forward. Yet, much like the real-world techniques of memory erasure and identity alteration we explored in Citadel Season 2, it is always worth questioning the reality hidden behind the most sci-fi elements on screen: we might just discover they are far more real than we ever anticipated.
My Dearest Assassin, the Thai film that landed on Netflix in 2026, opens with a piece of information that seems to contradict the basic scientific principles we all learned in school: the rarest blood type in the world is called Aurum Blood and, as the film’s introductory text claims, it is shared by a mere 0.00000625% of the population. Most viewers might dismiss this as a groundless fantasy, yet the few who choose to investigate will find themselves uncovering a reality that rarely surfaces in standard high school textbooks.
The Aurum Blood of My Dearest Assassin is rooted in a true story: there exists an incredibly rare—and immensely precious—type of blood possessed by only a handful of individuals worldwide. Known as “Golden Blood,” it represents one of those scientific revelations we might never have encountered were it not for the narratives shared on Netflix.
The true story of Aurum Blood in My Dearest Assassin
In the science textbooks we studied as children, the narrative was relatively straightforward: there are four primary blood groups—A, B, AB, and O. Their distinction lies entirely in the presence of the A and B antigens within our blood: If we possess only the A antigen, we belong to group A; if only B, we are group B; if we have both, we are AB; and if we possess neither, we are O. To this classification, the so-called “Rh factor” is typically added—a separate antigen independent of the previous groups: if we have it, we are “Rh positive,” (+) otherwise, we are “Rh negative” (-).
This was the extent of the story we knew until My Dearest Assassin. When we begin watching the film on Netflix, we encounter this mysterious “Aurum Blood” that apparently only a few individuals in the world possess, a notion that seems to conflict with everything we have ever known: according to the blood group classification mentioned before, the rarest type would be AB- (with Rh negative), which belongs to only 0.6% of the population. Consequently, there is no whisper of a blood type even rarer—one ten thousand times less common than AB-—in the concepts we studied at school.
And yet, the golden blood of My Dearest Assassin truly exists, and to understand it, one must uncover a further level of detail in the scientific classification of blood types.
The complete Rh system
In reality, when we speak of Rh positive or negative, we are referring to a specific Rh antigen, the D antigen. In truth, there are over 50 Rh antigens: beyond the D variety, the most significant are C, E, c, and e. The reason we have simplified our foundational knowledge, limiting it to Rh(D), is that it is the specific antigen capable of triggering massive hemolytic reactions during blood transfusions.
These hemolytic reactions function much like viruses: the first time a virus enters our body, we develop antibodies; the second time we come into contact with it, those antibodies will attack and destroy that virus. Similarly, in blood transfusions, if we are Rh negative and receive Rh positive blood, we will develop antibodies for the Rh(D) antigen. If we receive Rh positive blood a second time, we will experience a severe hemolytic reaction that can lead to immediate, lethal complications. For this reason, it is of fundamental importance to verify the compatibility of the blood we receive before every transfusion.
The real “Golden Blood”: The Rh-null phenotype
There exists a strictly limited group of individuals in the world who do not merely lack the Rh(D) antigen: they also lack every other minor antigen within the Rh system. For these individuals, receiving “normal” blood—even standard Rh negative—can provoke hemolytic reactions: this type of blood is called Rh-null, known in scientific parlance as “Golden Blood.” The film My Dearest Assassin has rendered the name more poetic, calling it “Aurum Blood” in its original version, utilizing the Latin word Aurum, which means, indeed, Gold.
As Wikipedia explains, golden blood was first identified in an Aboriginal Australian woman in 1961. Since then, approximately fifty individuals worldwide have been found to have this blood group, of whom fewer than ten are donors. It is estimated that the rarity of these individuals is roughly one in every 6 million people. The golden blood of My Dearest Assassin is described in the film as a blood type possessed by only 0.00000625% of individuals: a figure that would correspond to one person in every 16 million, making it slightly rarer than the actual Golden Blood.
Why had we never heard of it? Because in the vast majority of cases, the minor antigens of the Rh system do not cause significant reactions, and thus they have not entered the general knowledge regarding blood groups. But for those exceedingly rare individuals who possess golden blood, this is a fundamental distinction: they can only receive blood from others who share their own (extremely rare) blood group.
For those who would like to find out more, we suggest exploring the topic further in this article by MedicineNet. We are, of course, not hematologists, but simply fans of movies and TV series.
The meaning of Aurum Blood in My Dearest Assassin
A scientific concept as unique as the Golden Blood is the perfect foundation for a thriller like My Dearest Assassin. The fact that these individuals are so rare naturally makes them targets: they are the true “absolute universal donors,” the only people who can give blood to anyone in the world, including those who share this same nearly extinct blood group. In a world where everything is assigned a value, this blood becomes so precious that a powerful organization might even consider killing to get it.
The film takes this biological rarity and turns it into a struggle for survival. The real meaning of the Aurum Blood in My Dearest Assassin is that it “marks” these individuals as something so valuable they are forced to hide. They live in constant fear of powerful people who want to hunt them down and take control of their blood. In this way, a scientific fact is transformed into a life-or-death manhunt that is incredibly gripping to watch on screen.
And in the meantime, one of the many films we watch on Netflix, together with our natural curiosity, has led us to discover something we would have otherwise only encountered in an advanced hematology textbook. That’s the beauty of the world of cinema.
