Fiver years after the destruction of the Death Star, Luke Skywalker fears there is no hope as the remnants of the Imperial fleet are readied for war under the command of Grand Admiral Thrawn.
Using Ysalamiri to sever a developing Jedi clone's connection to the Force allowed mentally stable Jedi clones to be created - a discovery Thrawn would use in his war against Luke Skywalker and the New Republic.