Eurekia
the cursed sword that costs a squire
2d6 damage. May be drawn once per combat — but only from the scabbard kept by Hamfund the Squire, who must be present and findable. For every swing, roll a d6. On a 1, the squire is slain and Eurekia vanishes forever.
The sword is hungrier than its bearer realizes. The scabbard does not contain Eurekia. The scabbard contains the squire's tether to it. When the tether snaps, the sword goes wherever swords go to wait for the next bearer.
Wretched Royalty, Hamfund the Squire, Blade of Your Ancestors (parallel royal blade)
Whether Eurekia is the sword's name, its forger's name, or the cry of its first wielder's discovery is unwritten. Whether the scabbard could be guarded by a different squire if Ham is replaced is open — possibly the sword binds itself to whoever inherits the scabbard. The cycle of squires through the royal line could fill a whole campaign.