In Chasm City, Sky Haussmann is the son of Titus Haussmann, the head of security aboard the Santiago. Sky discovers that he is not in fact his father's son, and was an infant 'momio' awakened by Titus secretly after the death of his own son. As such Sky Haussmann is immortal. Sky's story is told in a series of dreams as a counterpoint to the waking life that Tanner Mirabel experiences throughout Chasm City. The planet Sky's Edge was founded after the Flotilla of ships from Earth landed there and mockingly named in Sky's honour as a reminder of the action he took to ensure that the Santiago would be the first of the Flotilla to arrive.
Sky's greatest crime and best-known action was the ejection of entire rings of reefersleep caskets in order to gain an advantage in speed over the other craft of the Flotilla, destroying the "momios", or "sleepers", that were to be the colonists for the new world of Journey's End. This strategy meant the Santiago had less mass than the other ships and so could decelerate later and arrived at Journey's End first.
Because of his crime, Haussmann was apparently crucified after the other colonists landed on Sky's Edge. However, he managed to get a stand-in to be martyred, while Sky himself entered reefersleep for several decades, before eventually fleeing the planet.
Sky Haussmann is the centre of a pervasive cult, and those who worship him do so as if he were a god. This bizarre cult has developed an indoctrinal virus that alters the infected's perceptions, often giving them physical symptoms similar to stigmata or whole chapters of Sky's life as simulated experiences. The virus is designed to reprogram the victim, in a sense.
Sky shows up again as a minor character in Redemption Ark, but calls himself only "H"; he meets and allies with Nevil Clavain. He has killed and replaced the Mademoiselle for the 'greater good of the galaxy.' Haussman captures Clavain and convinces him of the best course of action to combat the Inhibitors. By aiding Clavain in his efforts to set up the expedition, largely responsible making possible for the successful evacuation of Resurgam and Clavain's efforts to save most of humanity.