Shadow Calling

Shadow Calling was an advanced form of Force Concealment, created by Darth Trayus before his assault on the Shadow Imperium. The technique allowed him to mask his presence in the Force and cause any who sensed it to believe what he wished them to. In his particular instances of using it, he was able to fool even his closest friends, allies, and family in not sensing his fall to the dark side of the Force when he came to them as Cadden Blackthorne, though Garen Starfall even noted that he had a strong, persuasive aura about him; when they were approached as Darth Trayus, they were unable to sense his true identity, though Cazzik Wyn was able to determine something familliar about him, and the more exposure he had to Trayus the more familliar the man became. It was noted by Trayus, however, that people that knew him well or those especially skilled in detecting others in the Force could be able to detect who he really was. It remains unknown if this is truly the case.

Note
It is undetermined if this was considered an exclusive dark side power, as Darth Trayus was the only individual to use it.