|Map||Basic Data||Planetary Image|
|Affiliation:||Unknown, formerly Imperium|
|Class:||Dead World, former Mining World|
Signus Twelve was a series of mining outposts located within the Cassium Belt, during the Horus Heresy. During the second year of the Heresy, the outposts were among a dozen targets on Ultramar's eastern edge to be attacked by the Traitor forces of Princep Maxiums Horgoth Nyr. Each was chosen to merely act as a bread crumb to lead the commanding Legio Praesagius Princeps Dae Vergos, into an ambush on Drooth II. Before leaving the Cassium Belt, the Dark Mechanicum and Traitor Titans had completely destroyed Signus Twelve's outposts.