The dragonborn in Icespear was talking about moving all this treasure to Tarkin Hall, did so via a portal.
Tarkin Hall, in [[Cados},, used to be a military outpost, used for a war with the Barbarians in the time of Parsy I
Princess Parsy commanded troops out of Tarkin Hall
The sword needed for, um, entry to Tarkin Hall was that of Princess Parsy. We got that. The blood has to be royal blood from the Parsy line, of which Princess is the only known attainable one since Parsy is a big fat liar.