system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] What is the difference between a Dark Jedi and a Sith?
gpt
A Dark Jedi is an individual trained in the way of the Jedi who has fallen to the Dark side. A Sith subscribes to the Sith philosophy but doesn't necessarily have to have been a Jedi previously. 

When Anakin Skywalker fell to the Dark side, he became a Dark Jedi. Once he accepted the mantle of Darts Vader and became Palpatine's apprentice, he became a Sith.