The Sivians are an advanced race of humanoid beings, originating from the planet Sivos.
A group of Sivians led by Viro were travelling to Naro-Atzia, using the Lazy Comet. Leo Fitz, a Human, pretended to be a Sivian with the help of an Iriscope, so that he could travel to Naro-Atzia and find a replacement Cryo-Freeze Chamber. He also hid Enoch on the ship. However, Fitz was discovered by the rest of the crew and Viro threatened to kill him. Using his engineering skills, Fitz made Viro spare his life by repairing various mechanisms on the ship. Seeing how useful Fitz was, Viro decided to throw the rest if the crew in space. Fitz rescued the rest of the engineers with the help of Enoch, killing Viro in the process. Because the crew would be executed for mutiny upon arriving at Naro-Atzia, Fitz then decided to take the Sivians to Kitson.