Gryphonne IV

Gryphonne IV was a Tempestus forge world with Mars-grade defences, the Legio Gryphonicus, and an eight-system empire called the Octad. Hive Fleet Leviathan ate it in 998.M41 anyway. Survivors ran to Tolkhan with data-cores and a handful of Titans; eight and a half billion workers were left. Patterns from this world still turn up on Guard tanks that outlived their birth-forge.