The Dark Side Score
Characters have a Dark Side score, representing how close they are to losing themselves to the corruption in the Force and being twisted into servants of evil. Each game table has its own approach on how to adjudicate when a player's actions qualify them for increasing their Dark Side score, with the explanations on page 93 of the core rules serving as a guideline. As your GM and the Force itself in this game, I have my own way of handling these things.
From my experience with Star Wars, I understand the Dark Side to be a corruption of the Force, a draw towards violent destruction rather than the natural order of things. Acts of cruelty, calling upon the Force in anger or hate, or using your power to prey upon people weaker than you are all expressions of the Dark Side and will earn an increase in your Dark Side Score. Attempts at justifying evil actions by their good outcomes won't mitigate the increase, and are perfectly reasonable in-character thoughts to rationalize evil actions to oneself. Sometimes you really do have to do something evil to get the necessary outcome. Another thing to keep in mind is that the Dark Side's corruption isn't always flashy and obvious. Sometimes I may not warn you that an action will increase your Dark Side score, especially if it's a small transgression that's become a pattern of mild selfishness and cruelty.
Attaining a Dark Side score equal to your Wisdom score does represent your complete fall to evil, but we won't be using the optional rule that you lose your character at that point. This era of play includes heroes who have fallen to the Dark Side, and there are methods of atonement to reduce your Dark Side score and become redeemed, difficult as that may be.
Any other specifics regarding the Dark Side and recovering from it will have to be sought out in-character by experts in the field.
