Uchiha Sasuke is a lonely boy.
Yes, he has (had) his family. He has (had) his only brother, father, and mother. He has (had) his clan; he brings (brought) them wherever he is.
He is still a lonely boy.
Since he was a child, all he did was to look at someone who continuously give him the bare minimum. His dad who constantly praised Itachi and compare him to his prodigal son. His mother who could only smile and kissed his forehead.
And Itachi.
His older brother who poked his forehead when lying and spouted every excuses known to men.
When that traitorous bastard massacred his entire family, he only have himself—up until his death.
But he would not die until he had Itachi's blood on his hands.
He would pierced his Kusanagi right through the center of his beloved brother's heart; just like how he did to every Uchiha he killed for the sake of 'peace' of Konoha.
He would see to it why Susanoo is the god of sea and storms for he destroys everything with waves of chaos and drowns everything into the depth of sea.