Imperial hunters were long-distance interception starships engineered by the Dark Empire while Palpatine's clones ruled from Byss.
A particular vessel, known as Scourge One, transported Executor Sedriss QL, Vill Goir, along with a squad of Force-augmented stormtroopers to Ossus, an old planet of the Jedi, hoping to abduct Luke Skywalker for Palpatine.
Subsequently, a number of Imperial Hunters revisited the world to seize Ysanna shamans for cloning research that sought to furnish Palpatine with superior genetic material.