Daario Naharis, the commander of the Second Sons, was notably absent from Game of Thrones' final two seasons. Michiel Huisman portrayed the suave sellsword for the majority of the character's arc. Despite not giving viewers definite closure on Daario, there were clues hinting at his fate.
Daario was first introduced in Game of Thrones season 3 as a lieutenant of the Second Sons. The company, under the command of Mero and Prendahl na Ghezn, was hired by the slaver city Yunkai to fight Daenerys' army. Daario refused to obey his superiors when they demanded that Daenerys be executed. The lieutenant killed Mero and Prendahl na Ghezn to take over the Second Sons and pledge his allegiance to Daenerys by helping her conquer a slew of cities. Up to this point, Daario was portrayed by actor Ed Skrein. When the character returned in season 4, Daario was recast with Huisman, confusing viewers in the process.
Not only was he Daenerys' key enforcer, Daario eventually became her lover as well. He played an integral role in the takeover of Meereen but their conquest went awry when the Sons of the Harpy attack during the opening of the fighting pits. Daenerys fled the area but was soon captured by the Dothraki. Daario was joined by Jorah Mormont in her rescue attempt but Daenerys took matters into her own hands. The group successfully took back Meereen from the Sons of the Harpy and abolished slavery in Slaver's Bay, renaming the area Dragon's Bay. Sadly, Daenerys put an end to her romance with Darrio and requested that he and the Second Sons remain in Meereen to keep the peace while she sought out the Iron Throne. The season 6 finale would be Daario's last appearance on the series. As far as viewers are aware, Daario and his men stayed in Meereen at the request of their Queen during the fight for the Throne.
It was speculated that Daario and the Second Sons would return in Game of Thrones season 8 to act as extra forces in Daenerys' attempt to conquer Westeros. In the end, Daario was left to oversee the newly established relations in Meereen. Daenerys made it clear that Daario would be a distraction and his overly heroic acts would likely seal his fate. She believed that he would serve a more effective role if he remained in Dragon's Bay as a peacekeeper. Daario was clearly still enamored by Daenerys and her death would have crushed the commander. It would be likely that Daario remained in Essos for the rest of his days to carry out the last request from his former lover. Maybe Drogon took Daenerys' body back to Meereen as her final resting place.
Daario could get a more conclusive ending in George R.R. Martin's A Song of Ice and Fire book series, the novels that served as the basis for Game of Thrones. The character appeared in A Storm of Swords and the most recently published installment, A Dance with Dragons. In the books, Daario was the commander of the Stormcrows. He aided Daenerys in her conquests but was later given to Yunkai as a hostage. Daario's fate will ultimately be resolved in the forthcoming novel, The Winds of Winter, or the rumored end of the series, A Dream of Spring.