Invisable Man wrote:i believe you are right to the most part except that they would know the light and the dark side, i believe you are getting this mixed up with the qoute, he has no restrictions on the force. which meant that he could tap fully into the powers of the dark side,
You are right. When I say he can use both dark and light side powers I meant he doesn't have to be dark or light side to perform them. He can be neither, and still tap into the dark to attack someone, he can also defend and heal himself with the light side. You talk about the physical side of it, try talking about the emotional side of it: that's what force users do, they don't use their arms or legs to perform powers, it all comes from strong emotions, and the mind itself. Watch the films closely. You can't use dark side powers if you feel no anger, fear or hate. You can't heal and protect if you cannot remain calm and fearless.
I know he returned to the light, however Darth Revans holocron is not good it's evil, and that holocron is Revans. That makes him responsible for it, regardless of the fact he returned to the light. I haven't read anything to suggest that they have got to be a Sith Lord FOREVER to be responsible for their actions in past, present and future to be a Sith'ari. And first time Sith'ari was mentioned is KOTOR when Yuthura ban talked to Revan about the perfect Sith.
INFO I FOUND ON SITH'ARI
Darth Revan is a potential candidate, since his destroying of the Star Forge greatly reduced the Sith's numbers, at the same time, brought about the eventual (close) purge of the Jedi Order. His holocron also provided Bane with the foundation to create the Rule of Two, which would lead to the Jedi Order's downfall. Later, Kreia alluded to the idea that Revan was above the influence of the Dark Side. Revan may also kill the true Sith in the unknown regions.
Darth Bane is a candidate, as he provided Kaan with the knowledge of the thought bomb leading to the destruction of the Brotherhood of Darkness. Afterward he (Bane based on Revans rules) instituted the Rule of Two to make the Sith stronger than ever. It is also alluded to in Darth Bane: Path of Destruction that Bane is fulfilling an ideal that he found in the prophecy and Darth Revan's holocron.
Darth Vader is another candidate. His killing of Darth Sidious ended the Rule of Two and eventually brought forth the rise of Darth Caedus and Darth Krayt. However, he is the least likely candidate as the prophecy states "he will be free of all restrictions". All of Vader's limbs were cybernetic, disabling him from using Force lightning and other physical abilities.
REVAN
-Can use dark and light side without it influencing him
-Was sith, provided Bane with knowledge to kill Sith Council and rule of two
-Killed Sith, destroyed star forge and discovered true sith
Bane
-There is nothing to confirm he can use dark and light powers without it directly influencing his decisions
-Was sith, responsible for killing Sith when Darth Revans holocron provided him the knowledge
-Passed on Sith knowlege through 1,000s years, however most important knowlege came from Revan.
REVAN IS THE SITH'ARI