The season finale of "Game of Thrones" will bring together the main contenders for the Iron Throne in the hope of forging an unlikely alliance to fight the greater threat of the White Walkers and its army of the dead. Based on the last episode, Beyond the Wall, we could safely assume that they are almost at the edge of the wall at Eastwatch.
Now that Daenerys has pledged to join Jon Snow in the battle, the King in the North only needs to convince Cersei of the existential threat that the Night King poses to all the inhabitants of the Seven Kingdoms.
But unlike Daenerys, Cersei will prove to be a harder leader to sway and as Tyrion astutely pointed out, the Queen is already scheming on how to turn the desperate situation into her advantage. As circumstances stand, Cersei could get the upper hand after the battle in the north is done.
Cersei could refuse to send troops
Cersei used to mock the stories about what exists beyond the wall and there is no reason to believe that she will change her views anytime soon. Seeing the captured wight may persuade her otherwise but it does not guarantee that she will commit immediately to the cause up North.
Actually. she could refuse to send troops and wait for the combined forces of Daenerys and Jon Snow to be decimated by the Night King, which very likely could be the outcome.
Cersei could be forced by Daenerys to give a commitment under the threat of siege and dragons but in the end, she may betray them all by simply refusing to fulfill her end of the bargain.
How Cersei could defeat the Night King
First, no "Game of Thrones" fan is seriously contemplating the idea that Cersei will be able to hold on to the Iron Throne till the very end.
Cersei could eventually end up dead through the hand of the "valonqar" or his little brother should the prophecy of Maggy the Frog comes true.
It is reasonable as well to believe the prophecy because part of it already did came true as it predicted that Cersei’s children would die before her.
But in the event that it would all come down to Cersei to defeat the Night King, she actually has a weapon that she used before, wildfire.
And there is plenty of it in Kings Landing despite the fact that she blew the Sept of Baelor last season.
The Mad King kept them under all of Kings Landing and would have used it to reduce the entire capital into ashes had not Jamie interfered. Qyburn had already discovered it so Cersei already knew that there are much more hidden beneath the tunnels.
The extraordinary power of wildfire can certainly inflict damage to White Walkers and its army of the dead.
It is also not far out idea that Cersei would learn about dragonglass and how these could destroy the White Walkers.
With an additional army from Essos armed with dragonglass and an arsenal of wildfire, Cersei could have a fighting chance with the Night King.
