Thetis

Give me Liberty, or give me a planet of equal or greater worth. – The immortal words of Imperial Commander Modestus, first Lord of Liberty.

Brought into the Imperium in M35, this system is dominated by the political machinations of the Merchantile Council of Last, a group of hereditary peers that have overseen imports and exports from the system for four millennia, with a brief break in M38 following the Unpopular Uprising. The Council has holdings all over the principal planets of the system, but makes its presence felt most obviously through the opulent Last Palaces on Liberty itself.

Liberty is a small, civilised world with hundreds of settlements in dense clusters across rolling hillsides and bordering calm, fecund oceans. Despite having few raw materials of its own, the world supplies a surprisingly high tithe through its excellent trade network, which extends across the Hesiod-Siculus subsector. It supplies some regiments to the Imperial Guard, which are unremarkable beyond their excellent sharpshooters. The planet is ruled by a seething aristocracy currently topped by the Dam-immortél Liberty, seemingly a foppish coquette, but possessed of an acute – and ruthless – mind. Libertines, as the planet's inhabitants are known, are generally characterised as overly-focussed on profit, but otherwise honorable, good men and women.

Cacoph Tertiary is the largest of the three innermost worlds, and the only one with permanent settlements of any note. The Cacophians are hard workers, known through the system for their creative approach to problems and their awful liquor. 

Rubicon provides numerous heavy infantry regiments to the Guard, which are renowned for their sturdy demeanour and cussedness. Their officers are universally unimaginative; referring to the Liber Rubicus in almost all circumstances. This book, issued to every officer on receipt of their rankpins, contains a massive compendium of every extant report of engagements in which the Rubicon regiments have served since pre-Imperial dominance. While the tactics within are staid and conservative, they provide useful insight to the present day. It is a history penned in the blood of loyal infantrymen.