Though many of his initial ideas eventually changed when the time came to begin writing the Prequel Trilogy, one staple remained untouched since Lucas initially discussed it at a conference in 1981: ...

"Obi-Wan Kenobi ... A New Hope." The series begins with Kenobi in exile on the familiar desert planet of Tatooine after the fall of the Jedi Order and the rise of the Galactic Empire.

The very first face-off between Obi-Wan Kenobi and Darth Vader in Star Wars was in A New Hope, which was also when Obi-Wan sadly died. Obi-Wan did not fear Darth Vader or death at all, though.