Syll Nenn, an Umbaran woman from the Legends continuity, had a twin brother named Nyss Nenn. Despite not being able to directly use the Force, these siblings possessed a unique ability that made them seem Force-dead to those who were Force-sensitives. This power enabled them to both diminish the powers of Force users and conceal themselves within the Force.
In the year 41 ABY, Darth Wyyrlok tasked Syll and her brother with the mission of capturing Jaden Korr along with his clone, known as the Prime. The twins pursued Korr and his clone across the uncharted territories of the Unknown Regions, a hunt that led to Syll's untimely demise. While firing upon an escape pod containing Khedryn Faal, Korr deflected one of her laser blasts with his lightsaber. This redirected energy struck the Nenns' ship directly, resulting in an explosion that fatally threw Syll against a wall. Nyss then attempted to complete their mission, but he too met his end at the hands of Korr.