The Sleepers are young sorcerers or those with high sorcerous potential who have been kidnapped over the centuries by the Thitans and taken to Nidhol. Once there they were given an Elacite Crystals which put them into a deep cursed sleep. Currently there is nearly a thousand sleepers in Nidhol. After they fall into a coma they are taken below the Temple of Souls to a large open Chamber of the Sleepers where they are laid to rest, under an enchantment that keeps their bodies alive and preserved just as it had been when they first touched an Elacite Crystal. In all the centuries of doing this only once has a sleeper awakened, and she disappeared 5 years ago much to the consternation of the guardians of the Temple. So far though they have managed to keep her disappearance secret from the Thitans. Each of these sleepers are actually living the lives of the Ehoshim soul stored in the Elacite Crystal they touched, often across multiple worlds of the Heptarchy. The goal of the Thitan in doing this is to try to create sorcerers who could tap into all the aspects of Aaru. Despite their great power, the power of the Thitans is hugely diminished from what it once was, before the Shattering of Aaru. This is something most Ehoshim would find abhorrent, and any Sorcerer who awoke would be considered Aessuri, but this is what the Thitans want.