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.

tulaksam said:

Read the wording on the Horde again. It says that while the Horde is attacking, the opponent cannot declare defenders.

So, with Dragon Sight, when it is time for the opponent to declare defenders, the Horde is not yet attacking. Therefore, the Horde's text has no effect and the opponent can declare as many defenders as they want.

Then, when the Horde is declared as an attacker, it's text kicks in. Well, all the text prevents is the opponent declaring defenders. It does not retroactively undo the declaration of defenders that have already (legally) been declared, nor does it remove any characters from the challenge. The defenders are legally participating and the Horde cannot do anything about that. There is a big difference between "cannot declare defenders" and "cannot defend," or some other nullification of the character's pre-established status as a defender.

So, the long and short of it is that there is no combo. The Horde stops defenders from entering a challenge in the first place, but doesn't place any restrictions on characters that are already participating. Dragon Sight essentially nullifies your own Horde's ability.

I assume this same reasoning then applies to 'Stealth'?

PorkUnit said:

Yep. It's one of the reasons why Dragon Sight honestly hasn't made the cut in my Summer Targaryen decks. When all the dragons, Khal Drogo, and whoever likely has Aegon's Blade all have Stealth and Dany's Horde doesn't work well with it either it just doesn't ever really seem to be worth the effort in helping me.

It's a strong effect, but with the character base I typically find myself with it just doesn't synergize that well.