Drogon

"Dracarys!"

- Daenerys Targaryen telling Drogon to breathe fire.

Drogon is one of the dragons born in the Dothraki Sea, along with Viserion and Rhaegal. He is named after Daenerys' late husband Khal Drogo. He is distinguishable by his black and red colored scales, and red-black wings. He is the largest and most aggressive of the three hatchlings.

Physical appearance and personality
Drogon is slightly larger than his siblings. Most of his scales are black, shadowing red ones that run down his back and neck. His wings and frills are black-red mix, down to the wing-bones which are black. His eyes are orange-red. Over the course of the series he has grown considerably, from being roughly the size of a kitten in Season 1 to the size of a small whale in Season 5.

Drogon is the least shy of the three dragons when it comes to interacting with humans, albeit for the worst. He is by far the most aggressive of the three, easily agitated and quick to anger, as seen when he is a juvenile and he snarled at a Yunkai wise master when he approached his mother. He is also the first to react to orders and takes the initiative in confrontations, as seen when Daenerys ordered her dragons to burn Pyat Pree or when the Wise Master threatened her, he was the first to jump to his mother's defense. He often seeks his mother's affection, and is often seen being caressed by her. However, even she isn't safe from his anger, as seen when he snarled at her without warning when she tried to defuse a conflict between the three. That said, he is fiercely protective of his mother, and will fight viciously in order to defend her, ignoring wounds if needed, as seen when he attacked the Sons of the Harpy in the Pit. It appears that he can sense when Daenerys is in danger, and if he does, he will rush to her aide. His larger size also makes him take a dominant role among his siblings, shown in how easily he stole a lamb from Viserion and Rhaegal, the latter two not daring to fight but instead squealing for him to share.

Season 1
He is born along with his two siblings after Daenerys has their eggs placed on the funeral pyre erected for her deceased husband, Khal Drogo. As she rises unharmed from the ashes of the pyre on the morning following the funeral, he climbs on her shoulder and lets out a powerful scream, announcing the return of dragons to the world.

Season 2
As her small khalasar travels east, Daenerys tries to get Drogon to eat, but he refuses the raw meat she offers, just as his siblings do. Later, while Daenerys is staying at Qarth, she teaches Drogon to breathe fire for the first time, roasting a small piece of meat, which he then eats. Drogon and his siblings are kidnapped to the dismay of Daenerys. In a meeting with the Thirteen, Pyat Pree, a warlock, reveals he has taken them to the House of the Undying and claims that he is eager to reunite Daenerys with her children.

After Daenerys enters the House of the Undying, she eventually finds her three dragons chained to a small dais. Pyat Pree suddenly appears and chains Daenerys with magic, saying that her dragons make his magic strong, that she makes the dragons stronger, and thus she must stay in the House of the Undying forever. An unconcerned Daenerys whispers "dracarys" to Drogon, and after a couple of tries, he spits a large plume of fire at Pyat, igniting the warlock's robes. The other two dragons follow their brother's lead and the three of them burn Pyat Pree alive, free themselves and Daenerys from their chains, and set the House of the Undying alight.

Season 3
Drogon has grown significantly since leaving Qarth, and is about the size of a small dog by the time Daenerys and her party reach Astapor. He swoops into the water and catches a fish, which he then cooks in mid-air and devours. Daenerys notes that he is not growing fast enough for her to use him to conquer the Seven Kingdoms in the immediate future.

At the slavers bay, she speaks with Kraznys mo Nakloz, as they attempt to work out a deal for his slave soldiers, the Unsullied. Daenerys says she will take all eight thousand Unsullied, including those in training. To this Kraznys laughs at her and says even with the wealth she possesses she could afford hardly over one hundred Unsullied. Daenerys surprises him by reminding him she has Dragons, and she will give him one. They strike a deal that she may have all the Unsullied, as well as those still in training, in exchange for her biggest dragon.

Sometime later the exchange is made and Daenerys meets with the Good Masters and gives the chained Drogon over to Kraznys, who in turn gives her the golden scourge which signifies absolute authority over the Unsullied. Once the Unsullied are under her command, Kraznys angrily comments that Drogon does not obey him, to which she responds, in Valyrian, that he does not obey because dragons are not slaves. Daenerys orders Kraznys's death with a harsh "dracarys". Drogon then takes flight and strafes the guards and Good Masters in the walls above the plaza

After the Sack of Astapor is finished, Daenerys' khalasar and her new Unsullied army march out of the city, Drogon and his brothers flying overhead.

Drogon and his brothers are present in Daenerys' tent when a Wise Master from Yunkai arrives to entreat with their mother. Drogon, now about the size of a large dog, aggressively barks at the Master when he gets to close to Daenerys. Later the Slave Master has two slaves place a chest full of gold near Drogon. While the two talk Daenerys throws a piece of meat to Viserion, and Drogon attempts to steal it from his brother. When the negotiation goes sour, Drogon growls at the Slave Master for threatening Daenerys. Scared for his safety, the Slave masters tells his slaves to take back the gold and attempt to leave, Drogon stops them in their tracks, hissing and growling.

Season 4
Drogon and his siblings are now the size of small horses. He quietly rests his head on his mother's lap, taking joy as she caresses him. When his two siblings come back with a dead lamb, he joins the fight over the carcass. His mother tries to calm him down, and without warning, Drogon snaps at her with a hiss; a warning to not interfere. He then roars and goes to contest the kill. Daenerys is shaken that she is losing influence over her "children", as dragons can never be truly tamed.

On the run from the Lost Legion, Asher Forrester, his uncle Malcolm Branfield and partner Beskha encounter Drogon inside a cave, but manage to escape. Asher later reports the find to Daenerys while asking for help, though she does not believe him, even with evidence to support the claim.

Following Daenerys' conquest of Meereen, Drogon, who is now the size of a small ship, kills and eats the goats of a local goatherd. The goatherder lays the charred bones of his flock before Daenerys in her throne room, hoping he has not angered the new queen and that this was a form of punishment. Daenerys apologizes for Drogon's actions and promises to pay the goat herder back three times the worth of his lost goats.

Dany is later dismayed to learn that Drogon has killed the young daughter of a another goatherd. She tearfully confines the two smaller dragons to the catacombs of the pyramid while Drogon remains at large, having last been seen over the Black Cliffs.

Season 5
Daenerys confides in Daario Naharis that she has no idea where Drogon has flown off to.

After the public execution of Mossador, Daenerys encounters an even further grown Drogon on top of the Great Pyramid. She reaches out to him, but Drogon flies away at the last moment.

Drogon apparently flew west, eventually winding up roving the skies above the shattered ruins of the Valyrian Peninsula, where he was glimpsed by Jorah Mormont and Tyrion Lannister, who were traveling through the region to avoid pirates. Massive and majestic, Drogon's unexpected appearance rendered the typically chatty Tyrion speechless and seeing him again also enraptures Jorah. Drogon's flight unfortunately distracted the pair long enough for them to be attacked by Stone Men.

While Daenerys attends the grand re-opening of the fighting pits at the Great Pit of Daznak, a large group of Sons of the Harpy appear and attack her council and the spectators. While trying to escape, Dany and her small group become surrounded by the Sons with no chance of escape. Drogon suddenly appears, flying out of a flame burst and begins to attack, burning the Sons with his fiery breath and biting them with his powerful jaws. Temporarily retreating in terror, the Sons regroup and retaliate by throwing spears at Drogon, wounding him slightly, but, when Dany commands him to fly away, he does so, with Dany on her back.

Later, Drogon lands atop an impressive hill in a sea of green grass. Though Dany tries to convince him to take her back to Meereen, Drogon is still recovering from his wounds and is uninterested in flying back. Daenerys wanders away to find something to eat, but she is quickly surrounded by a Dothraki khalasar.

Season 6
At some point following Daenerys's takeover of the Dothraki, she senses Drogon trailing her. She slips away and rides him around the khalasar before landing and giving a rousing speech mounted on his back. He is significantly larger than he was during the battle in Meereen. Eventually, Drogon carries Dany to the Great Pyramid of Meereen, which is under siege by the Masters. Daenerys discusses terms of surrender of the masters in Meereen. The masters foolishly mention slaughtering the dragons, which angered their mother. Drogon answers Daenerys's call, lands next to her and moves one of his wings allowing her to mount his back. As Drogon takes flight, Viserion and Rhaegal break out of the catacombs and join their brother in the sky at last. At Dany's command of "dracarys", Drogon leads his brothers in immolating the slaver fleet with dragon fire, decisively ending the Second Siege of Meereen.

Some time later, Drogon and his brothers accompany their mother and her large army on a voyage to retake Westeros by soaring above the armada.

In the books
In the A Song of Ice and Fire novels, Drogon is much the same. He is the largest and most aggressive of Daenerys's dragons. She named him in memory of her recently deceased husband, Khal Drogo.

Balerion the Black Dread, the dragon of Aegon the Conqueror, was also colored black with red highlights. Generations later, Daenerys Targaryen thinks that her newly hatched dragon Drogon resembles descriptions of Balerion so closely that he is actually a reincarnation of Balerion's spirit, though she gives him a new name for his new life.

After killing a child and escaping, Drogon's whereabouts are unknown for a long while. He never returns to Dany at the Great Pyramid, and Tyrion doesn't definitely see him on the way to Meereen —however, he does glimpse a flying creature with leathery wings, who may well be Drogon, in the same chapter that is being adapted in the scene which unambiguously includes him in the TV series. Drogon does not come to Daznak's Pit in the books to save Daenerys; he is drawn to the Pit by the smell of blood and fresh meat from the numerous gladiatorial battles (some involving animals). When the guards around and inside the arena try to attack him, Drogon goes on the rampage, causing over 200 deaths as people are either killed by the dragon or trampled in the panic to escape. Only one person in the arena - an animal handler called Harghaz who Daenerys suspects merely wants to make a name for himself as a dragonslayer- manages to seriously injure Drogon before the dragon kills him.

Daenerys refers to her three dragons as "brothers", but there is actually no specific reason to think that their eggs were all laid by the same dragon, or if the three eggs were even found in the same place or gathered individually. She may call them "brothers" more in the figurative sense that they were raised together.