Because I think he ultimately does care for the good of the realm. He wants to build a kingdom where there isn’t poverty and exploitation, like the world he grew up in.
That’s essentially what he tells Tyrion in Season 5, for what it’s worth (I know the books and the show are different beasts by now, but still.) According to the recent EW issue, Varys says he wants “peace, prosperity. A land where the powerful do not prey on the powerless.” And then he goes on to say the lines about a ruler loved by millions, heard in the trailer. I, for one, believe him.
I do as well. Varys isn’t motivated by money – he got all of that he needed in Pentos. We know he’s got motivations other than power – otherwise, why try to save Gendry?
And then I go back to his childhood. Sold as a slave, horrifically mutilated, homeless, physically abused, survival prostitution – Varys has known what it is to be poor and exploited more than most, and I think he wants a systemic solution.
Varys feels so deeply for the exploited and mutilated that he employs a network of orphaned spies whose tongues Illyrio cuts out for the sake of discretion? That’s in interesting way of expressing empathy. At least he’s kind enough to teach them how to read and write.
Well, that’s where Varys’ utilitarianism kicks in. He’s willing to wade through a pretty big ocean of blood to get to the promised land. So yes, one last generation of mutilated children to make a world in which children are safe.
RFTIT Tumblr Backup 