Star Wars Episode III: Revenge of the Sith
Anakin Skywalker is anointed as Darth Vader, in order to create the First Galactic Empire.
In the fight with his former master Obi-Wan Kenobi, Skywalker is mortally scarred, and thus began his physical transformation as Darth Vader. Anakin loses himself as he approaches death, truly becoming Darth Vader.