this is a disclaimer.
AN: skopos is the Greek word for 'purpose/objective'.
skopos
It is pathetic, really, proof of how far the man has fallen, that he cannot see why Vader has just saved his life. Twenty years ago he would have understood instantly. Twenty years ago, he would not have provoked the boy so far in the first place.
Twenty years ago he knew better than to push too far too fast, to bring all the weight of his powers down on the boy the way he's doing now. Twenty years ago he would have stepped back and waited for the war to wear him down, for others to do his work for him, waited to drip poison into the boy's mind little by little, gain his trust, prove himself worthy of loyalty. He did a better job with that girl Jade than he's doing here.
Not that Vader minds.
Better that Luke kill him in the heat of battle than in cold blood. Better the Emperor die the way Maul did than Dooku; it's too soon for that. One murder does not a Sith Lord make. Vader should know. Guilt and horror at his own deeds will drive Luke even further away from him, temporarily at least. The boy still feels too much, still cherishes too many ideals.
But then Luke dodges him and collapses his blade and refuses to fight and his calm as he does so is the only thing about him still reminiscent of Obi-Wan and Vader finds himself wondering –
Why did he stop the boy from killing Palpatine?