Here we go, the finalie gave us three important clues as to how things might end. Qwyburns fascination with the wight and Cersi saying explicitly she is willing to destroy everything. Funny how they also said kings landing holds ten times as many people as the army of the dead. I think there was a reason that was pointed out. Wonder what sent the mad king mad? Read on.
Heres a possible set of events for the end. The night king is going be beaten but the ruler issue will be the last thing to happen in the show. This is what I see going down.
Jamie will run back to Kings Landing to prepare a defence. Jon and Dany will be right behind him.
The battle for Kings Landing begins and there are massive casualties on both sides, eventually the city is breeched. Jamie and Cerci are in the red keep looking death in the face. Cerci sends for Qwyburn who in his studies has found out how to raise the dead, all the dead, as wights...no night king needed. Bear in mind he can already do this on a limited scale as per the mountain.
Cerci plans to raise all the battle dead and simply kill everyone. Jamie fought the war meant to end all this and is horrified. A million plus wights? In the populated south?
He is left with the same choice as he once had, kill the monarch he swore to defend or watch unimaginable harm occur.
Cerci then goes into labour. Jamie is there sword poised but if he strikes he kills their child too. He cannot bring himself to do it.
Qwyburn completes the rites, hundreds of thousands of dead rise. All hell breaks loose with the dead attacking everyone. Cerci dies in childbirth. It was a boy, giving us the little brother prophesy. Grimly it would still be born as a wight, possibly a white walker.
Jamie realises what he has to do, Kings Landing is doomed either way and conveniently its also happens to be sat on a massive bomb full of wildfire. If he can set it off he saves Westeros.
Turns out the mad king was sent mad due to having visions of the future, the horror was too much for him, "Burn them all!" suddenly makes a whole lot of sense. He might have lost his sanity but still prepared for what he knew was coming.
Que Jon and Danny on dragons trying to keep the wights penned in whilst Jamie leads a suicide squad to set the wildfire off.
He succeeds and Kings Landing is destroyed utterly. So are the wights. I can see a lot of our favourite guys getting killed. My shout would be Beric setting it off with his flaming sword - that would clearly make it lightbringer and give the reason he could be brought back.
After this that leaves Jon and Dany together ruling north and south with Dragonstone as the new capital. Aaand duh duh du du duh duh...
Thanks for reading.