Game Of Thrones Season 8 Breakdown: What 'The Last Of The Starks' REALLY Means
4. The Starks & Varys Know Too Much
Despite the fact that Dany implores Jon not to tell anyone, he tells Sansa and Arya about his past. Luckily for Dany, though, he swears them to secrecy too, so Sansa inevitably and almost immediately tells Tyrion, who is so concerned about this secret getting out that he tells Varys. Which is a little like trying to plug holes in a boat by shooting it repeatedly with several scorpions.
Giving Sansa the information and further seasoning her dislike and distrust of Dany as a potential ruler is one thing, but giving it to Varys is something else entirely. The moment he found out that there is a better candidate for the Iron Throne - particularly as questions over Dany's volatility are further raised - was only ever going to lead to him doing something about it for "the good of the realm."
Varys knows too much now and it's either going to lead to him killing Dany or to him being killed in an attempt to overthrow or kill her. Quite which of those you think will happen likely depends on how much you think Varys' status as the mouthpiece of the realm protects him from the machinations of the Great Game.