The Gray Jedi
The Gray Jedi are neither Light nor Dark, but rather both. But the problem here, Gray Jedi are those Jedi candidates who did not decide to follow either the Light or Dark side.
These Jedi are known also as Jedi Apprentices who are able to use both sides of the force. Luke Skywalker in "Return of the Jedi" was able to use the Force Grip on the Gamorreans to compel them unconscious, but not dead. He also used the Force Jump to escape from the Sail Barge. Another Force Power allowed him to levitate See Threepio in the Ewok's throne on Endor.
He was "still" an apprentice. However, after becoming a light Jedi as he rescued his father from the Dark Side, he was drawn to the light side - away from the darkness.
Yes, Gray Jedi are existing, but it is often misunderstood - such Jedi are called Gray Jedi in correct term, but they are only the apprentices, not full developped Jedi. Many people who believe in this paradoxon, that the Jedi - the most powerful of the Jedi or "Force users" - are able to use both sides, do not realize that those who use partly both sides of the force are the Gray Jedi, and with this, only Jedi Apprentices.
They cannot master the Force, the Force masters them. They become stronger, but they become strong in the end when they decide for the Light, or the Dark Side of the Force.
They have limited powers, not full developped skills, not fully trained they are.
...Jedi Mitth'raw'nurida
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