“A farm boy with nothing becomes the galaxy's last hope — and chooses to save a father instead of defeating an enemy.”
The Force flows through him instinctively — destroying the Death Star with targeting computers off is the iconic proof.
Two duels with Vader mark his growth. In Episode VI he overpowers Vader — then stops, choosing mercy.
In Episode VIII he projects himself across the galaxy to cover the Resistance's escape — at the cost of his life.
Hope given a body. Luke knows anger and fear lead to the dark side, yet instead of suppressing his emotions he makes the right choice while feeling them. His decision to save his father wasn't strategy — it was pure faith. That naivety is what brought down the Empire.