A Star Iron Sword is already a weapon of immense value (see one-handed weapons list for statistics) but one on which the Black Order Star Iron Imprisonment has been cast is doubly so. Such a weapon contains a shred of a Black Mage's soul, and can cast spells under the command of it's wielder.
Most such weapons can use spells of the first or second circle when commanded to do so by the wielder. These spells do not require a channelling roll, but will always cost the Spirit in the blade their full fatigue cost, and the spirit only regains 1 fatigue per day. The spirit has a maximum pool of 15 Fatigue. The blade is restricted to spells that do not require an attack roll. When such a blade is first found the wielder will have no idea which spells the spirit of the blade knows (the GM will need to determine the power level of each blade) and must determine them through experimentation. A blade with spells beyond the second circle is even more valuable.