Tolaris Shim was a Jedi Master. Shim was an active member of the Jedi Order during the time of the Great Sith War. Somewhat of a radical amongst their peers, Master Shim firmly believed that all Jedi at some point and in some form or another walked along the path of the dark side of the Force. To this end Shim also believed that any Jedi who turned away from the light was ultimately destined to commit atrocities against the innocent. Furthermore, once said atrocities are committed by the fallen Jedi, Shim believed there could be no redemption, only atonement. The catalyst for Shim's staunch position was the redeemed Ulic Qel-Droma, whom the Jedi Master believed was only eligible for indemnity.
Regardless of Shim's conservative opinions on the subject, the Jedi Order tasked Master Shim with researching the hows and whys behind a Jedi's fall to the dark side. In 3996 BBY, ten years before Qel-Droma's death, Shim completed their research and compiled their findings into the Four Stages of the Dark Side.