...And yet, there is my son with Shmi in his eyes -- a product of love, before the storm. He is no Jedi, for his passion blows too hot, but perhaps he is not Sith, either. He is an instrument of change. He is the catalyst at the centre, the fulcrum on which pivot fates. To see him is to be blinded by the glory of the Force that orbits him like living netting.
"Balance to the Force".
Luke is last/first Jedi, trained by the last Jedi Master.
But... the way of the Sith is that they kill their Master, and then are killed by their Padewan in turn. Vader killed Sidious. But then Luke killed Vader. Thus Luke is also last/first Sith.
I really doubt George Lucas was this smart, but it still works...