Kinslaying is the act of slaying a family member and a great taboo in the Seven Kingdoms. Whoever commits it is dubbed a kinslayer. Any individual who slays a member of their own family is believed to be cursed forever in the sight of gods and men.
The taboo associated with kinslaying is strong enough to stay the hand of even the most ruthless men. Tywin Lannister would have liked nothing more than to kill his son Tyrion the day he was born, because his mother died giving birth to him and for the shame he brought on their family for being born a dwarf. However, Tywin felt that House Lannister was above the shame and curse of kinslaying, so he relented and let Tyrion live.
If a mother dies in childbirth, her baby is not held to be a kinslayer because there was no intent and it wasn't really their fault. The reactions of family members to the child can still vary, however, sometimes irrationally blaming the child for the mother's death. Tywin always blamed Tyrion that his mother Joanna Lannister died giving birth to him, though in contrast his brother Jaime insisted that it wasn't his fault.
Known and alleged kinslayers
- King Aegon II Targaryen, who fed his half-sister Rhaenyra Targaryen to his dragon.
- Prince Maekar Targaryen, who accidentally dealt a mortal head injury to his brother, Prince Baelor Targaryen during the trial by seven of Ser Duncan the Tall.
- Robert Baratheon, who killed Rhaegar Targaryen, who was actually his cousin due to intermarriage between the Baratheons and Targaryens.
- Ser Gregor Clegane, suspected to have murdered his young sister as well as his father.
- Craster, who sacrifices his male offspring to the White Walkers.
- King Stannis Baratheon, who conceives a shadow assassin with Melisandre to kill his brother Renly.
- Melisandre later insists to Stannis that she must sacrifice King Robert's bastard son Gendry. Stannis is uneasy about this and Davos Seaworth points out why: Gendry is his own nephew and he would be spilling his own blood. Davos concedes that Renly had wronged Stannis, declared himself king ahead of his older brother, stole his rightful bannermen to raise an army, and Renly himself would have killed his brother Stannis when their forces clashed on the battlefield. Renly was no innocent, but Gendry is just an innocent bastard boy. Davos verbalizes Stannis's doubts, who hesitates whether to spare or kill Gendry as it would be an unlawful kinslaying. Eventually the matter is taken out of Stannis's hands, when Davos helps Gendry escape.
- Stannis becomes a kinslayer once again along with his wife Selyse when they allow Melisandre to burn their daughter Shireen in the belief that R'hllor will allow them to survive to reach Winterfell and defeat House Bolton. Selyse feels remorse and attempts to save Shireen, but by then it is too late. Stannis feels he has no choice as if they do not receive divine intervention from the Lord of Light, all of them including Shireen will freeze to death in the blizzard halting there advance. Regardless, unlike her uncle Renly, Shireen was entirely loyal to Stannis, and he has now truly become a kinslayer by any measure.
- Ser Jaime Lannister, who murders Alton Lannister, his distant cousin, in his attempt to escape captivity.
- King Robb Stark, is accused of it by Lord Rickard Karstark when the former is about to execute the latter. This was due to the distant blood ties between House Stark and House Karstark, and it is debatable if Robb would be officially labelled a kinslayer as a result.
- Tyrion Lannister, accused of murdering King Joffrey, his own nephew, at his wedding feast. Becomes an actual kinslayer after murdering his father, Tywin Lannister. Tyrion later sarcastically quipped that because his mother Joanna died giving birth to him, from a technical standpoint he had "killed" both of his parents, making him the greatest Lannister-killer alive.
There have been several characters who contemplated kinslaying:
- Randyll Tarly felt that his eldest son and heir Samwell was a fat and bookish boy utterly unworthy of the martial traditions of his family or to lead House Tarly, so he sought to disinherit him. Randyll took Sam riding, and bluntly ordered that Sam would announce that he wanted to join the Night's Watch and foreswear all right to inheritance. He then promised that if Sam did not join the Night's Watch, he would take Sam out in a "hunting trip" and kill his own son in such a way that it looked like an accident. The terrified Sam subsequently joined the Watch.
- Tywin Lannister said that after Tyrion's mother died giving birth to him, he wanted to throw him into the ocean in his grief. Ultimately he didn't, however, because Tyrion was a Lannister.
- Roose Bolton explains to his bastard son Ramsay that he fathered him by brutally raping a miller's wife. The miller had married without his consent as his lord, so Roose had the miller executed by hanging him, and he took the miller's wife under the same tree from which her husband's corpse swung, with her fighting him the whole time. The next year she showed up at the Dreadfort with the infant Ramsay, and in anger Roose was about to throw him into the nearby river to his death - but when he looked on Ramsay's features he saw that he was his own son, and the taboo against kinslaying stayed his hand.
In the books
In the A Song of Ice and Fire novels, the taboo against kinslaying is pretty much the only reason that neither Tywin nor Tyrion ever try to kill Joffrey. Soon after Joffrey is crowned king it rapidly becomes apparent that he isn't simply vicious and cruel: he's a sadistic madman. Moreover, Joffrey is so utterly impulsive that he publicly, brazenly commits acts of petty cruelty that even the most ruthless kings of the past would have hesitated to commit, simply because it would be counter-productive. After Joffrey needlessly starts a city-wide riot, Bronn openly asks Tyrion why they don't simply assassinate Joffrey given that he causes far more problems than he solves, and moreover, actually has a pliable younger brother (Tommen) whom the Lannisters could easily use to replace him as their puppet king. Essentially the only reason Tyrion gives is that he won't kill his own nephew.
Characters in Westeros who have never met Daenerys Targaryen, as they start to hear news of her string of conquests in Slaver's Bay, are sometimes appalled to hear that her husband Drogo killed her own brother Viserys as she watched. This is largely because they didn't know how much of a monster he was, or that he violated Dothraki law by drawing a sword in Vaes Dothraki and threatening Drogo's unborn son, and thus Drogo was entirely within his rights to execute him. Then again, in these discussions other characters point out the well-known madness that runs in the Targaryen family, and accurately guess that Viserys may have been not much better than his crazed father King Aerys II Targaryen.
In the books Stannis Baratheon never admits that he ordered Melisandre to send the shadow demon against Renly, thus it is unclear if he is actually guilty of kinslaying.
Theon Greyjoy is sometimes inaccurately accused of being a kinslayer for his alleged execution of Bran and Rickon Stark, though as a highborn hostage and ward of the Starks he was not actually their blood relative.
"Alton Lannister" in the TV series is a renamed version of Cleos Frey from the books. Cleos's mother Genna is actually Tywin's sister, making Cleos a first cousin to Jaime. The TV series apparently renamed Cleos for fear that the audience would be confused why a man named "Frey" was fighting for the Lannisters in Season 2 (before the Freys turn on Robb Stark in Season 3), so they renamed him as a Lannister to make clear what side he is on. Jaime didn't kill Cleos Frey in the books, rather he accompanied Brienne of Tarth on the mission to return Jaime to King's Landing for a prisoner exchange, but he was killed by outlaw bandits along the way. The TV series later made clear in "A Man Without Honor", however, that "Alton Lannister" isn't exactly the same character as Cleos Frey, but is instead a far more distant cousin. Jaime has difficulty even remembering who Cleos's mother is, and Alton says she is Cynda Lannister, not Jaime's well-known aunt Genna. So on the one hand, Jaime was never a kinslayer in the books but the TV series has him kill Alton. On the other hand, the TV series changed the relationship of "Alton Lannister" so he actually isn't a very close relative of Jaime at all - it is debatable how much the shame of kinslaying would apply to a fifth or sixth cousin. Moreover, it's vaguely implied that "Alton" was willing to give his life in a heroic escape attempt if it would free the famous Jaime (though he didn't understand that when Jaime said Alton wouldn't survive the escape attempt, he meant that he would kill Alton to distract the guard).
Killing a relative by marriage, instead of a blood relative, is still considered kinslaying, because in a spiritual sense they have become part of the same family. It's possible that it isn't considered quite as bad but only by a matter of degree, i.e. killing your own brother or son is generally seen as somewhat worse than killing your own brother-in-law, though both are still reviled. Lord Tytos Blackwood's son was killed at the Red Wedding, and he notes that one of Lord Walder Frey's wives was herself a Blackwood, but apparently the bonds of marriage mean nothing to Lord Walder. This wife was actually the mother of Lame Lothar Frey, meaning that Lame Lothar was responsible for the death of his kinsman Lucas Blackwood - given Lothar's club foot he might not have participated in the fighting directly, but he was one of the main masterminds who orchestrated the massacre and gave the orders. The exact relationship between Lame Lothar's Blackwood mother and the main Blackwood family hasn't been given, though the TV series might have condensed this. Just as kinslaying is considered a worse crime than regicide, violation of guest right is considered to be an even worse crime than kinslaying, so any kinslaying which occurred at the Red Wedding is overshadowed in the narrative by how outrageous and unthinkable it was that Lord Walder murdered guests under his own roof.
According to Ygritte, the gods hate kinslayers, even when they kill unknowing. She told Jon Snow a story about a wildling king named Bael the Bard, who kidnapped the daughter of one of the Stark lords. One day the daughter returned with an infant, who eventually became the new Lord Stark. Thirty years later, the son fought against Bael (unaware of their kinship) and killed him. Bael recognized his son and allowed him to kill him, for he could not shed the blood of his kin. When the Lord Stark returned from the battle and his mother saw Bael's head upon his spear, she threw herself from a tower in her grief. Her son did not long outlive her: one of his lords (presumably a Bolton) peeled the skin off him and wore it for a cloak.
George R.R. Martin has said that there are considered to be different degrees of kinslaying, depending on the relationship and circumstances, though these may be unofficial. Degrees of kinship are taken into account: killing your sibling or parent are both reviled, and what is often thought of as "kinslaying", but killing a parent is considered the worse of the two. Killing an uncle or nephew is also viewed negatively (such as when Stannis pondered killing his bastard nephew Edric Storm, replaced with his other bastard nephew Gendry in the TV series). All of these variants are considered to be much worse than killing a distant cousin, though this is still frowned upon (Robert Baratheon killed Rhaegar Targaryen, even though they were second cousins, but Robert wasn't universally reviled for this). The aristocracy of the Seven Kingdoms is heavily intermarried and many succession wars centered around rival claims between different groups of distantly related relatives. Martin specifically explained that Rickard Karstark was "stretching" when he warned Robb Stark that if he executed him it would be considered kinslaying, given that the Karstarks branched off from the main Stark family around one thousand years ago.
Martin also said that the circumstances of kinslaying are weighed by degrees (perhaps unofficially). Personally killing your own kin (with a sword, arrow, poison, etc.) is reviled, and hiring an assassin to specifically kill your kin for you is nearly as detested. If two brothers are leading rival armies against each other in war (such as Stannis and Renly), there are several variable outcomes. If Renly had announced to his army that he would reward the man who killed Stannis, or gave standing orders that Stannis was not to be taken alive, it would be viewed very negatively, though not quite as much as if Renly personally killed Stannis. If Renly publicly announced strict orders that he wanted Stannis captured alive, but Stannis accidentally ended up getting killed in the battle anyway, it would not be seen as nearly so negative. If Renly attacked Stannis's army but did not think to give specific orders about whether he wanted Stannis taken alive or dead, it would be seen as morally falling somewhere between the two, because he should have given more specific orders if he was concerned about avoiding kinslaying.
Therefore, personally murdering your own parent is considered to be the absolute worst kind of kinslaying - such as when Tyrion confronted his father Tywin with a crossbow and shot him dead. Robb Stark would, objectively, not be greatly blamed for executing Rickard Karstark, because he was a very distant cousin, and rather than "murder" Robb was within his rights to execute him for treason - though he chose to formally carry out the sentence with his own sword in hand. 
- ↑ "Mhysa"
- ↑ "And Now His Watch is Ended"
- ↑ "The Night Lands"
- ↑ "The Ghost of Harrenhal".
- ↑ "Second Sons"
- ↑ "The Dance of Dragons"
- ↑ "A Man Without Honor"
- ↑ "Kissed by Fire"
- ↑ "The Lion and the Rose"
- ↑ "The Children"
- ↑ "Hardhome (episode)"
- ↑ "Cripples, Bastards, and Broken Things"
- ↑ "Kill the Boy"
- ↑ So Spake Martin: Kinslaying in Westeros.
- ↑ So Spake Martin: Kinslaying in Westeros.
- ↑ So Spake Martin: Kinslaying in Westeros.