A tiny rock and ice planet that is now missing much of its ice, Ilem was part of a grand project by a Hegemony dictator known as Grebosht the Mad. His aim was to drop enormous chunks of Ilem's ice on the surfaces of otherwise uninhabitable desert planets in the hopes of creating sustainable lakes and seas. Wiser heads than he pointed out that diverting a comet was more plausible, but Grebosht executed those who disagreed with him. Grebosht's career was surprisingly long given his loose grip on reality, mostly because his projects employed large numbers of batarians.
Today, Ilem lies abandoned, Hegemony spy drones still orbit the planet, but it is doubtful anyone on Khar'shan is paying attention to what data they send back.