This post contains spoilers through Season 7, Episode 7 of Game of Thrones.

“Out of all the people in Thrones, Jon, of all people, is probably the least up for incest,” Kit Harington told Entertainment Tonight last month. “But we don’t know whether they’re related.”

The actor was talking about the romantic tension between his character, Jon Snow, and Daenerys Targaryen—a tension that Game of Thrones, sometimes gracefully and sometimes awkwardly, has been meticulously building over the course of its seventh season. It’s been a tension complicated by the fact that while, as Harrington suggested, viewers didn’t know for sure whether the two were related … we have also been preeeeetty sure that the two are related. Sunday’s episode, “The Dragon and the Wolf,” confirmed it: Jon is not, in fact, the illegitimate son of Ned Stark; he is in fact the legitimate son of Ned’s sister, Lyanna, and her husband Rhaegar Targaryen. Who was also the older brother of one Daenerys Targaryen. Which would, yep, make Jon Snow, né Aegon Targaryen … Dany’s nephew. Which would make the consummation of their attraction, as one of the final scenes of the season … extremely complicated.

Game of Thrones is a show that has depicted slaughtered children, and sexual violence, and martial violence, and torture both psychological and physical; it is a show that, often, looks at conventional notions of morality and scoffs at their quaintness. Incest in some ways is no different: It’s a taboo that Thrones has generally regards with a mixture of horror and shoulder-shrugging acceptance. Dany herself is the product of incest—her parents were brother and sister—as were Joffrey, Myrcella, Tommen, and Cersei’s (alleged) unborn child. Cersei and Jaime represent one of the longest-standing romantic partnerships of the series. Gilly is both the mother and the half-sister of baby Sam. Yara Greyjoy, having not seen Theon since they were children, initially flirted with him—an elaborate prank meant primarily to remind her brother of his diminished power on the Iron Islands.

Incest lurks everywhere in this world. And while it is sometimes treated as a moral failing (Cersei and Jaime, together, have never been paragons of anything save for savvy accessorizing), it is also, often, treated as a political one. Incest, in Thrones, is a situation that is also a metaphor—for what happens when people get too insular, too myopic, too unwilling to see beyond themselves. It is the Westermarck effect, gone terribly wrong. It is a warning about what can befall the world when narcissism gets politically weaponized.

Dany and her nephew Jon come from a long line of people who, having “the blood of the dragon,” were reluctant to marry outside that line, thus diluting the blood in question. That’s one of the many ways Game of Thrones’s history parallels the real world’s: Incest, of course, was once common, particularly among nobility. It is thought that King Tut suffered from an array of physical maladies brought on by at least two successive generations’ worth of interfamilial marriages. Charles II, the last of the Spanish Habsburgs, suffered from disabilities that came from 16 generations of inbreeding. Charles Darwin married his first cousin; his work on inbred plants led him to fear that the couple’s children, seven of whom survived into adulthood, would suffer the ill effects of the familial connection.

Historically, then, in the known world and beyond its continents, incest has given rise to a sweeping bit of hubris: People’s attempt to preserve their blood lines ended up, often, compromising them. The practice that took its name from the Latin incestus (“unchaste, impure”) ended up proving itself all too literally.

Whether Dany and Jon will have children—children who might in their own way fall victim to this sad irony—is an open question. For now, their union has made for one of Game of Thrones’s more twisted plot twists. As Alan Taylor, the director of several of the show’s episodes, including last week’s “Beyond the Wall,” told The Daily Beast: “There’s no secret that this is where this is going. Readers of the book have known that things were heading towards this destination for a while. Even the characters in this story know it’s heading in this direction.” Some fans cheered the movement of “Jonerys” from the realm of fanfic and into the realm of, simply, fic. Others gagged at it. Others were simply confused by it. (So much so that Newsweek, in a nod to the inevitable, recently enlisted the help of a psychosexual therapist to reassure fans that “there’s nothing wrong with you for wanting to see aunt and uncle get it on.”)

The reactions have been as mixed as they are in part for the simple reason that Jon and Dany are not Jaime and Cersei. They are good people, fundamentally. They grew up separately, in different places and different worlds. And, of course: They do not currently know that they are related. There are Luke-and-Leia vibes to the courtship between the last of the Targaryens; they are protected, in some sense, by their ignorance. And their relationship, as such, seems primed to provoke, rather than outrage or disgust, something simpler: questions—about intimacy, and its expanses, and its limits.

That puts the relationship between Dany and Jon in league with other such relationships in literature—which are often calibrated to be scandalous, yes, but which are just as often calibrated simply to be complicated. They may provoke judgment; they also, however, often demand sympathy. Chris and Cathy, in Flowers in the Attic, are victims of abuse at the hands of an evil grandmother. Emmeline and Richard in The Blue Lagoon are victims of a shipwreck and its attendant isolation. Little Charles and Ivy in August: Osage County are the victims of ignorance: They sort of understand their relationship to each other. And also they very much do not understand their relationship to each other.

Some literary portrayals treat incest as a profound—perhaps the profound—violation of the order of things: In One Hundred Years of Solitude, the members of the Buendía family live in constant fear that the results of their intermarriages will come to haunt them (in this case, via children born with the tails of pigs). In John Irving’s The Hotel New Hampshire, John and Franny’s intimacy gives way to an incestuous encounter. In James Ellroy’s White Jazz, the protagonist David Klein harbors an incestuous attraction to his sister. In Jeffrey Eugenides’s Middlesex, the narrator’s grandparents were siblings. There is often a cyclical inevitability to these stories: a sense of mistakes made in one generation, transmitted to another. A sense of destabilization at the most fundamental levels. A sense of doom. In the Harry Potter series, Voldemort is descended from a family in which cousins regularly marry.

But other portrayals—in American pop culture, in particular—use relationships between siblings and pseudo-siblings as vehicles through which to examine anxieties: about intimacy, about otherness, about the state of the modern family. Maeby and George-Michael in Arrested Development. Cher and Josh in Clueless. Margot and Richie in The Royal Tenenbaums. Kathryn and Sebastian in Cruel Intentions. Dexter and Debra in Dexter. Even Greg and Marcia Brady in A Very Brady Sequel—an on-screen coupling that poked fun at the very real fling between Maureen McCormick (Marcia) and Barry Williams (Greg).

The treatments of incest here range from the tragic to the taunting; what they have in common, though, is the same thing that makes the shipping of Dany and Jon so uniquely bizarre and, from a literary perspective, compelling: They blur lines. They occasionally poke fun. They often poke holes. They suggest, overall, a world that is much more complicated than it might initially seem to be.

In Thrones’s case, as the show moves into its final season, it has managed to set up conditions in which Dany and Jon are complicated in part by the fact that they are at once people and allegories: They are both lovers and rivals, both new acquaintances and lifelong relatives. They suggest order in the world and, now, the threats against it. “The Dragon and the Wolf” is a paradox, because the dragon and the wolf, it turns out, are one and the same. In one way, definitely, the couple’s newfound intimacy puts the “ewwwww” in “newfound”; it is the rough equivalent of the horror-movie character who, not being privy to the full picture, decides to open that door. More than that, though, their romance is a slow-moving tragedy. Because, in Thrones’s final season, Dany and Jon will very probably learn the truth. They will very likely suffer—through no fault of their own, but because of the failings of their fathers. They, the next generation of Targaryens, will be punished for the attitudes of those who carried the blood of the dragon and decided, despite it all, to keep it in the family.