When
Anakin Skywalker fell to the dark side and became
Darth Vader, he cast off his entire past. To further embrace this change, he had a
Jedi starfighter painted black to become his
Sith starfighter, and selected a similarly dark-hued
astromech droid to replace his former droid companion
R2-D2. Unlike the jovial, friendly relationship Anakin had with Artoo, Darth Vader regarded R4-K5 as little more than a functional tool.