The Garnet System is known for two place of special note. Garnet, the name giver of the system is a huge gas giant being mined by scooper ships from 14 different moons of the three dozen that surround it. Noble Houses own large tracts of Garnets atmosphere which is rich in anything from Helium, Xenon to over 300 substances that have a variety of uses in industrial production throughout the ultima segmentum. As a  hindrance to eploitation total of the atmospheric components stands its enormous volatility. Any oxygen trace produce large chain reactions. So the houses do not fight directly over their claim but rather have an odd tradition of solving conflicts.  This is when the second place of note comes into play.
The space hulk St. Ivy.
A gigantic structure that was drawn into the gravity pool of garnets  neighbor Greesom. The hulk is the biggest bloodsport arena in the sector and is administrated by the order of the poison ivy. The founder of the order, the mighty St. Ivy headed a crusade of volunteers  to cleanse the hulk before its many terrible inhabitants could befall her lovely home world of Adamas. She did succeed but not before the chaos lord of the hulk did draw it into the nether. The order survived the 150 years of void travel before the hulk dropped back into the real world, the Garnet system. By then the whole Hulk was sterilized at the cost of over 99 percent of the crusade. By chance,  accident or providence  all survivors of the crusaders were female, and on her deathbed St. Ivi got their promise to get an her own order of battle sisters who would keep all evil away from the hull.
To upkeep their station on the hull the Order of the poison Ivy stages arena and dungeon fights for the noble houses who can, with divine blessing of St Ivy, be determined as winner in an house conflict.