Dragon Sight requires that defenders declare themselves before attackers attack. Assuming that the defender does not have a Queen in play, the Horde are not able to be defended against. If the defender declares his defenders and the Horde decide to attack, what should happen to the declared defenders? Do they remain knelt even though they cannot defend?
Card text from both cards:
Dragon Sight: If if is Summer, when you declare a challenge type, your opponent must declare defenders before you declare attackers. The opportunity for your opponent to declare defenders after you declare attackers is lost.
Queen Daenerys's Horde: While Queen Daenerys's Horde is attacking alone, opponents who do not control a Queen character cannot declare defenders.