Originally a lieutenant in the Second Sons, a sellsword company, he takes over the company after killing his superiors Mero and Prendahl na Ghezn and then aligns with Daenerys Targaryen.
Daario is a Tyroshi sellsword, employed as a lieutenant in the Second Sons. He is apparently held in high enough regard by the company's co-captains, Mero and Prendahl na Ghezn, that they allow him to join them in contract negotiations and discussions of the company's future.
His weapons-of-choice are a stiletto and an arakh, with custom-made hilts in the shape of beautiful, naked women.
According to Daario, his mother was a prostitute, and he comes from no distinguished background.
Daario has an unusual code of honor for a sellsword: he won't sleep with prostitutes or kill innocents as he believes in making love with women who want to make love with him and killing those who want to kill him.
Daario Naharis is also an extremely capable and skilled warrior, which is first proven when he along with Ser Jorah Mormont and Grey Worm infiltrate Yunkai through a back gate where they fight and kill many Yunkish soldiers, eventually forcing the city to surrender to Daenerys and her army. His skills are proven once again when he kills Meereen's champion in a duel with ease outside the gates of Meereen.
Daario Naharis joins the captains when they visit Daenerys Targaryen, who hopes to convince them to break their contract with Yunkai and fight for her instead. Daario sees through Daenerys' bluff that she has 10,000 Unsullied, reminding her that she has only 8,000. When the Second Sons depart with Daenerys' offer and a barrel of wine, Daario's gaze lingers on the young queen.
Back at their own camp, Daario, Mero and Prendahl discuss the situation, with Mero and Prendahl deciding to assassinate Daenerys. At Mero's behest, a bedslave hands out random coins – Daario draws the Braavosi coin that indicates he is the one to do the deed. His only response is "valar morghulis" - "all men must die". That night, Daario, wearing the armor of an Unsullied slips into Daenerys' tent and takes Missandei hostage. He then presents the heads of Mero and Prendahl and informs her he has taken command of the Second Sons. Intrigued, Daenerys demands that he swear fealty to her. Daario bends the knee and swears the Second Sons, his sword, his life, and his heart to Daenerys.
Daario later assists in planning the siege of Yunkai, and is selected, along with Ser Jorah Mormont and Grey Worm to infiltrate the city and open the gates from the inside. The plan succeeds brilliantly, and Jorah and Grey Worm return to their queen triumphant. Daenerys expresses concern over Daario's whereabouts, but he appears a moment later, presenting Yunkai's bloodstained flag to her.
Ser Barristan and Missandei reveal that Grey Worm and Daario have been indulging in a bit of gambling; they have been at the contest since midnight and have missed a morning meeting with the queen as a result. Daenerys is very irritated to discover that their contest is a game of who can balance their sword for the longest, the prize being the honor of riding at her side when the march resumes. Daenerys assigns the pair to guard the livestock as punishment for their childish game. When they fail to move, she warns them that the "winner" of the contest must find a new queen, prompting them to drop their weapons instantly. Grey Worm's gaze lingers on Missandei, which Daario takes as a sign that he is interested in her, and points out that this problematic given Grey Worm's eunuch status. Grey Worm tells Daario that he is not a smart man for saying such things, to which Daario replies that would rather be a man with no brain and two balls. Later on, Daario slips away from his post to discuss "strategy" with Daenerys; he gives her flowers under the guise of a lesson in the botany of Slaver's Bay in which he points out that Daenerys must know the land she is to rule.
At the gate of Meereen, Daario volunteers to fight Meereen's champion in single combat after Daenerys rejects the rest of her inner circle from fighting. Daario declines the use of a horse, noting that they aren't as intelligent as humans. Daario ends the duel with ruthless efficiency, striking down the horse with his stiletto and decapitating the dazed champion with his arakh. After the Meereenese fire a volley of arrows in a symbol of displeasure, Daario urinates on the nearest one in a symbol of defiance
After Daenerys takes control of Meereen, Daario announces at a council meeting that the Second Sons have captured the 93 ships of the Meereenese Navy on his orders. When asked by Daenerys why the Seconds Sons took the navy without being instructed to, he responds by saying that he heard she liked ships.
Later on, Daario comes to Daenerys' private quarters of the Great Pyramid and brings her flowers. As Dany refuses him, he tells he has only two talents in his life: war and women. Daenerys asks him about his loyalty and Daario swears his sword and life are hers and asks her to let him do what he can the best, so to send him to kill her enemies. Instead, Daenerys focuses on the other thing Daario claims to be good at and orders him to take off his clothes. When he leaves her bedchamber the following morning he runs into Jorah, cheekily telling him that it's a good time to talk to Daenerys, as she is in a very good mood. Daenerys tasks Daario and the Second Sons with retaking Yunkai and killing every Master who has taken control. However, Jorah convinces Daenerys to give the Masters an ultimatum: to accept her abolition of slavery or die. She tells Jorah to "catch Daario before he leaves", and to send Hizdahr zo Loraq with Daario and the Second Sons as her ambassador to Yunkai.
Daario along with the Second Sons and Hizdahr zo Loraq returns from their successful mission in Yunkai and is present within in the Great Pyramid when Hizdahr suggests to Daenerys that she should reopen the fighting pits. Daario is later seen in Dany's bed explaining to her that he agrees with Hizdahr's suggestion to reopen the pits. He then goes on to telling her about his life growing up as a boy who became a pit fighter himself and how fighting in the pits made him the warrior he is today. He is the only one who will give her honest council. He also explains that a "dragon queen" is no queen without her dragons, which encourages her to visit Rhaegal and Viserion, who are chained in the catacombs.
Daario leads Grey Worm to a house where the alleged murderer of White Rat is hiding. He tells Grey Worm that his Second Sons overhear things that the Unsullied do not because they blend in with the local population. Daario is also able to deduce where a member of the Sons of the Harpy was hiding because he also understands fear, while the Unsullied do not. Later, he informs the Daenerys' council that the man they arrested has very little useful information since Daario had questioned him earlier. When Mossador murders the Son of the Harpy, Daenerys has Daario behead Mossador in public, causing a riot.
Daario brings Daenerys the news that Hizddahr zo Loraq, as well as many more supplicants are waiting for her. He states that it isn't neccesary for Ser Barristan to be present at Daenerys's side when she talks with Hizdahr, claiming that he is very much capable of protecting Daenerys against Hizdahr himself, which leads to Ser Barristan taking a walk in the streets instead. He is present when Hizdahr yet again tries to convince Daenerys that the fighting pits should be reopened.
Daario and Daenerys wake over the dead body of Ser Barristan. Hizdahr then enters to offer his condolences. Daario suggests to Daenerys that they could pull back to the pyramid district where they can set up a base of operation so that they can efficiently start working on catching the Sons of the Harpy. Daenerys chose to rather go with Daario's other suggestion, which involves apprehending the leaders of all the great families in Meereen and bringing them to her. Hizdahr states in shock of her decision that he is the leader of his family. Daario nods to the guards who then arrests Hizdahr. Daario is present alongside Daenerys in the catacombs when Daenerys threatens Hizdahr and the other apprehended leaders with the use of her dragons, Rhaegal and Viserion. Daario pushes one of the leaders before the dragons and watches as the master is burned alive then eaten. Later, while Daenerys is talking to Missandei she mentions that Daario thinks she should execute all the Great Masters and let the city of Meereen fend for itself. Daenerys chooses not listen to Daario this time and rather chooses to marry Hizdahr so that she can forge a bond with the people of Meereen.
Daario is bed with Daenerys after having sex, asking her if Hizdahr will soon take his place beside her in her bed. Daenerys notes a hint of jealousy in Daario, which she finds amusing and sweet. Daenerys says that her marriage to Hizdahr is purely for political reasons and is not because she loves him, assuring Daario that Hizdahr will not take his place as her lover. Daario asks Daenerys if she wants to marry him instead, even though it appears that Daenerys wants to, she says she can't. Daario goes on to tell her that she is a queen and queens can do what they like. Daenerys doesn't agree with this. Daario asks Daenerys to allow him to give her one more suggestion, which she allows. Daario suggests that on the opening day of the games in the fighting pits, she should apprehend all the Great Masters, Wise Masters and all other masters of note and execute them. Daenerys responds in horror of this suggestion that she is a queen and not a butcher, to which Daario replies that "All rulers are either butchers or meat".
Daario along with Daenerys, Tyrion, Missandei and Hizdahr are in the Great Pit of Daznak observing the opening match which is set to take place. The match features two fighters: one large man versus one smaller man. Daario states to Daenerys that she should gamble on the smaller man because Daario thinks that speed defeats size in combat. Daario is refering to himself when he says this because when he was a pit fighter himself he was also small, but this never stopped him from winning the fights, even when he was fighting against men that were much larger than him. Daario goes on explaining why this is so while twirling his dagger around Hizdahr's head, which makes Hizdahr nervous. Hizdahr disagrees with Daario's opinion on this matter, saying that in his experience watching the games in the fighting pits the larger men win over the smaller men almost every time. Daenerys responds to Hizdahr by saying that he may not be the right man to speak considering Hizdahr has never fought himself. The fight eventually end resulting in the larger man winning, just as Hizdahr had predicted, which leaves Daario with a sour look on his face because in this instant he was wrong.
Daario along with the others are all shocked when Jorah shows up as the second match is about to commence. Daenerys allows Jorah to fight in the match, and even though Jorah is outmatched for most of the fight he does end up winning the fight in the end. Just after the match has ended, Jorah throws a spear towards the podium where Daenerys is sitting, Daario makes sure the spear doesn't hit Daenerys by pulling her to the side. The spear that Jorah threw was revealed to be targeted towards a member of the Sons of the Harpy who had been sneaking up on Daenerys from behind. Daario looks in to the audience to realize that the Sons of the Harpy are there. Daario manages to fight off and kill many of the Sons that were trying to get to Daenerys. Daario witnesses in shock as Hizdahr is stabbed repeatedly in the chest as they are trying to escape from the podium, revealing that Hizdahr wasn't in league with the Sons of the Harpy after all as Daario had predicted. Daario, Daenerys, Tyrion, Missandei, Jorah and a hand full of Unsullied all run toward the senter of the arena trying to find a way to escape, but they instead find themselves surrounded by a huge number of Sons of the Harpy. Daario, Jorah and the Unsullied manage to kill several of them before they eventually realize that they stand no chance against such a huge number of Sons of the Harpy. Just as hope seems to fade away, Drogon appears in the arena scaring off most of the Sons and killing the rest. Daenerys ends up mounting Drogon on the back and flying out of the arena. Daario, Tyrion, Missandei and Jorah all look up to the sky as Daenerys flies away on Drogon.
Daario later strategizes – or rather argues – with Tyrion and Jorah in Daenerys's throne room. When Missandei arrives with Grey Worm, Daario throws a few barbs his way before firmly declaring that neither Tyrion – who has no tracking or combat skills – nor Grey Worm – who is still recovering – can come with them to track the queen down. Instead, Daario, declares, Grey Worm and Missandei must lead the Unsullied in keeping the peace, while Tyrion makes sure the city's politics don't bring the pyramids crashing down around them. Daario and Jorah then depart on horseback to find Daenerys.
Daario and Jorah's search takes them to the Dothraki sea. Daario gets Jorah to admit that he is in love with Daenerys, while musing that there is no escaping men like them in the world, and that he would like to see Westeros once Daenerys has conquered it. They eventually stumble across a circle of hoof prints with Daenerys's ring in the middle, leading them to discover that Daenerys has been taken by a Dothraki khalasar.
Daario and Jorah are climbing a hill in order to get a vantage point over Vaes Dothrak, which is where their search for Daenerys has taken them. While climbing Daario continues to make fun of Jorah about how Daenrys chose Daario over him, which keeps annoying Jorah. Upon reaching the top of the hill Jorah lays out a plan on how they are going to rescue Daenerys, a plan which innvolves sneeking into Vaes Dothrak during nightime unarmed, because if they were to get caught with weapons they would be killed (because all weapons are forbidden inside Vaes Dothrak), but if they were unarmed they could pose as merchants. Daario doesn't like the idea of giving up his weapons, especially his dagger, and is very reluctant about it, but he eventually agrees to hand them over. Just as he is about to hand over his dagger he notices the Greyscale on Jorah's wrist, Jorah assures Daario that it didn't touch him and that he is aware of the consequences it brings. Daario and Jorah then sneek in to the city during the night. They eventually stumble across the two Dothraki warriors Akho and Iggo in a back alley. Jorah tries to convince the two Dothraki that they are merchant whom have gotten lost in the city, but Akho doesn't belive their story and orders the other Dotharki to alert the city. Daario chases after Iggo while Jorah tries to fight Akhoo. Daario catches up with Iggo and breaks his neck before he can alert the others. Due to Jorah's greyscale condition he is unable to hold his own against Akho and is nearly killed right before Daario arrives to the rescue by stabbing Akho in the back with his dagger that he had lied about leaving behind. Daario then attemps to cover up the stabwound by smashing Akho's body with a rock, making it look like he was smashed to death and not stabbed.
As Daenerys and another Dothraki widow Ornela exit the Temple of the Dosh khaleen to get some air they run into Daario and Jorah. Daario seizes Ornela and is about to kill her, but Daenerys makes him stand down. Jorah urges them to leave quickly before the bodies of Aggo and the other Dothraki are discovered. Daenerys however has another idea which involves burning down the temple where all the Khals will be meeting to decide Daenerys' fate. Daenerys enters the temple and after a while of talking she pushes down all the pyres inside causing it to light on fire. Khal Moro attempts to flee out the back door but is unable to because it has been sealed from the outside and its guards have been killed by Daario and Jorah. Daario, Jorah and all the other Dothraki witnesses as Daenerys steps out of the burning temple alive. The Dothraki all bow to her, followed by Jorah, and Daario, who still is in shock of what he just witnessed bows last.
The morning after the burning of the temple, Daario is present with Daenerys when she confronts Jorah about his recent actions. Daenerys forgives Jorah and welcomes him back to her service, but Jorah refuses her offer and rather tells her to send him away again. Jorah then goes on to show Daenerys his Greyscale infection and confess his love for, which seems to make Daario not jealous but rather sad for Jorah instead, knowing he most likely will die. Instead of sending Jorah away to die, she rather commands him to look for "the cure" to his infection so that he can come back to her. As Jorah departs into the unknown, Daario and Daenerys along with the Dothraki start making their way back to Meereen.
On their way back to Meereen, Daenerys questions Daario on how ships she will need to take Westeros, to which Daario responds that in order to bring all the Dothraki and their horses, the Unsullied and the Second Sons, they would need a thousand ships if not more. Daario goes on to tell Daenrys that she isn't a ruler but rather a conqueror instead as her political rule in Meereen has proven. Daenerys suddenly orders Daario and the Khalasar to stop, and she rides off for unknown reasons. After a long while, Daario announces to the Khalasar thah he is going after her. As he is about to leave, they hear Drogon approaching, with Daenerys on her back. She reveals her true intentions to the khalasar and Daario, who looks at her with satisfaction and admiration.
Daario leads the Dothraki in their charge towards the gates of Meereen to end the masters' siege, removing the head of the first Son of the Harpy he encounters. As Daenerys leaves for Westeros she leaves breaks ties with Daario, fearing that bringing a lover to Westeros would be a detriment to her cause. Daario and the Second Sons are left in Mereen to keep the peace while a provisional government transfers power to the people.
A sellsword who has sworn himself to Daenerys Targaryen, Daario was a lieutenant with the Second Sons, the mercenary group hired to defend Yunkai from Dany. Originally dispatched to assassinate Daenerys, he killed his captains and helped Dany conquer the slave city instead. Daario served Dany as an advisor and lover and helped to secure Meereen from the Sons of the Harpy. Much to his disappointment, Daario was ordered to stay and watch over Meereen when Dany sailed for Westeros.