I have absolutely no idea. Martin has said that the ending will be bittersweet so I have a feeling that Tyrion and Arya (arguably the most loved characters) won't be alive at the end of it

As for who ends up ruling, I honestly couldn't guess it. I have a feeling that Jon won't be dead and will somehow end up leaving the Night's Watch, stop being such a mopey wet blanket and end up playing a big part. Any chance it's take him teaming up with Dani to save them not only from the wars in the Seven Kingdoms but also from the White Walkers? Jon being the ice and Dani being the fire?