The Eyeless were a telepathic humanoid species. They appeared to be made out of glass and shattered when killed. On Arcopolis, one of the Eyeless stole some green eyes from a young girl.
The Eyeless were explorers who foraged for technology, usually by agreement but sometimes by force. They came to the Fortress to use the weapon at its heart; however, the Fortress fought off the Eyeless, killing hundreds of them. In the end, the Eyeless activated the weapon, but it turned out to be a dud. (The Eyeless)