Lerxst was a Caeliar individual, a scientist who lived in the city-ship Mantilis. Lerxst was one of the Caeliar who worked on the Great Work apparatus in that city. In 2168, he was actively working when several crew and MACOs from the Columbia attempted to take over the apparatus to open a subspace tunnel that the Columbia could pass through back to Earth. However, an extragalactic feedback pulse was detected by the Great Work, and destabilized the entire system, leading to the destruction of their star and planet. Since the Caeliar seek to preserve sentient life, millions of the other Caeliar aboard Mantilis sacrificed their lives to protect Lerxst and the other Caeliar along with the Columbia crewmembers in the inner chamber during their travel through the tunnel. The Mantilis then crashed into a planet thousands of light-years distant from Earth. (ST - Destiny novels: Gods of Night, Lost Souls)