The Second Wave of the House Military was the first to be bred specifically for the War in Heaven. It infamously committed frequent acts of genocide, wiping out any species or culture which opposed or rivalled the Homeworld in any way. Its destruction of Ordifica and other Faction Paradox sites crippled the Faction for years and severed their contact with the Remote.
The Lethean Campaign was the last event of the Second Wave. (PROSE: The Book of the War)