Game of Thrones was well-known for its violence and ruthless battle scenes, and fans expected that the prequel series, House of the Dragon, would be very similar. However, season 1 of House of the Dragon primarily focused on the political build-up to the Dance of the Dragons, which meant that its death scenes were significantly less frequent than fans had come to expect from the world of Westeros.
Despite the fact that House of the Dragons has had few major death scenes, the ones it did have were vicious, and the ones to come are even more so. This is, in large part, due to the bloodthirsty nature of the Targaryen family, who have a history of destroying their enemies with such ferocity that nobody tries to betray them again. Across Game of Thrones and House of the Dragon (so far), ten major Targaryens can be judged by how high of a kill count they had, and the brutality of their kills.
10 Viserys III Targaryen — None
Fans like Viserys I far more than they liked Viserys III in Game of Thrones, as many happily cheered along when Khal Drogo killed him. He was racist toward the Dothraki and cruel to his sister, but it may surprise audiences to know that he never actually killed anybody.
That isn't to say that he was a pacifist. He threatened to kill Daenerys multiple times when he perceived her as a threat to his power. He was also seen threatening to kill Daenerys' unborn child, which further cemented his death warrant as Khal Drogo and Daenerys's saw he was going to be a major obstacle in the future they had planned. Viserys threatened violence to get what he wanted, but he ultimately had no power, either through respect or fear.
9 Rhaenyra Targaryen — No Humans; One Boar
Rhaenyra might be seen as the instigator of conflict when it came to the rivalry between herself and Alicent, but her actions were not bloodthirsty. Her only moment of brutal wrath was when she and Cristin Cole were attacked by the boar. She killed it in defense, but did not kill the white stag when she had the chance.
This is important, because it set the precedent that Rhaenyra would not cast the first blow. Alicent and her children openly tormented her and her children for years, and she didn't attack them. Even when she lost her father, her unborn child, and her crown, Rhaenyra hesitated—until she found out that her son had been killed. In that moment, Rhaenyra underwent a huge character transformation, with her reactions showing that future bloodshed will come as retaliation.
8 Viserys I Targaryen — 1 Human
Although Viserys was likely responsible for plenty of deaths throughout his reign (at least when it came to the executions of the worst criminals). However, there was only one that audiences directly witnessed. This was the death of Aemma, one of the most important people in Viserys' life, which agreed to. The forced caesarian might not have been done by his hand, it was certainly on his word and on his conscience.
While there is an argument to be made that Aemma would have died either way, the terror that Aemma felt in her last moments was a choice. The death scene was gut-wrenching, and the pain, fear, and betrayal Aemma felt can be place directly on Viserys's shoulders.
7 Aemond Targaryen — 1 Human, 1 Dragon (Accidentally)
Aemond is an intriguing character, because while he is somewhat comparable to Daemon as a second son who embraced violence for glory and power, but he generally knew when it was best to stop fighting. This can be seen when he comforted Alicent about his lost eye, rather than trying to retaliate.
Aemond did enjoy causing his nephews pain, either through cruel mockery or violence, but he did not intend to kill Lucerys and his dragon, Arrys. His sadistic side wanted them to fear him, but he didn't believe that his dragon, Vhagar, would end up taking it so far. Nevertheless, regardless of the accident, he has been responsible for these two characters deaths.
6 Aegon II Targaryen — 4+ (Indirectly)
While Aegon has not personally killed anyone so far in House of the Dragon, the Green Council conducted several executions in his name. As far as the audiences know, Cristin Cole killed Lyman Beesbury, Lord Merryweather and Lady Fell were imprisoned and killed, and Allun Caswell was hanged.
There were likely several others killed for Aegon's sake (and will certainly be more as the war ensues), but it's impossible to say any numbers for certain. Aegon himself may not be as bloodthirsty as his family, but his violent sexual behavior and eventual lust for public approval may motivate him to kill more directly in the future.
5 Daemon Targaryen — 20+
Although Daemon underwent a huge character growth over season 1, one thing that did not change was his violent attitude and, so far, he has one of the highest kill counts in House of the Dragon. He personally killed at least one person when he set the City Watch loose in King's Landing and also killed his first wife, Rhea Royce, to inherit the Runestone. He also killed another man in an attempt to fake Laenor's death, and Vaemond when he insulted his family. Not to mention the 16 soldiers that fell to his sword in the battle at the Stepstones.
In addition to having so many kills, Daemon's manner of killing was brutal as Vaemond's head was split in half and Crabfeeder was dismembered. While Corlys and Laenor might have actually defeated more foes in their military endeavors, Daemon seemed to enjoy utterly destroying his enemies.
4 Aerys II Targaryen (Mad King) — 50+
Aerys Targaryen was known as the 'Mad King' after he tried to blow up King's Landing; however, his actual kill count is uncertain. He fought in the War of the Ninepenny Kings, but it's unknown how many people he killed then or in the 20 years that followed.
However, fans do know that he executed everyone involved in the Defiance of Duskendale, which included every member of Houses Darklyn and Hollard. He also had Brandon and Rickard Stark executed after they tried to get Lyanna back. Fans know he intended to kill all 500,000 citizens of King's Landing, but his actual kill count is probably closer to 50, though more due to external interference than mercy.
3 Jon Snow (Aegon Targaryen) — 120+
Although Jon didn't intend to play a role in the War of the Five Kings, he ended up taking part in major battles that put his kill count in the hundreds. Despite initial resistance, the conflicts between the Wildlings and those in the Night's Watch, as well as the threat of the Night King, soon led Jon to kill those he couldn't reason with, including Qhorin Halfhand, Karl Tanner, and more.
Jon stood as a moral figure, and though his kill-count is high, the audience tended to agree that they were earned. In addition to an unknown number of kills in battle, Jon was personally responsible for 120 deaths, with the most significant and shocking being the assassination of Daenerys.
2 Rhaenys Targaryen — Unknown Number Of Civilians (Likely 100+)
Although many audience members expected Rhaenys to run away from court, her dramatic exit was quite the surprise, especially because the loss of lives was never acknowledged. She refused to slaughter Alicent and her family, but when she burst through the floor on dragonback, hundreds of unknown innocents must have died.
Between those who were directly above Meleys, those who were hit by shrapnel, and those who were in the dragon's path, it's hard to know exactly how many people were killed. Accepting that, it seems ridiculous that Rhaenys could struggle with ending a war before it began, yet felt no regret for the civilians that wound up as collateral damage.
1 Daenerys Targaryen — 500,000+
Daenerys has the highest kill count of any Targaryen shown on screen, thanks to the massacre she enacted in King's Landing. Prior to season 7, Daenerys killed 77 characters on-screen. In addition, Ser Barristan Selmy mentioned that she had executed 163 enslavers in Meereen. While this was a large amount of kills, most fans could justify them because she truly seemed to be a liberating force.
That moral line became muddied as the show continued. Daenerys' forces took down thousands of Lannister and Tarly soldiers, as well as executing Randyll and Dickon Tarly. Before and during the Great War against the Night King, she killed dozens of White Walkers, followed by executing Varys and slaughtering the Iron Fleet and much of King's Landing (which was estimated to hold 500,000 people). Though the exactly numbers are impossible to count, Daenerys proved herself as the deadliest player in the Game of Thrones.