Void Stone

An invisible but tangible gemstone, recovered from the treasure vault of the Hollow House in Session 42 and worn by Thalia as a necklace — set in a ring of her own thorns that wrap around an empty space and hold nothing anyone can see. Prodded with a tool, roughly one poke in ten passes clean through while the other nine tap something solid: it is not merely invisible, it is intermittently not there.

It was a container. Something was inside it, and in Session 55 the party let it out and watched it die — after learning what it had already cost.

Session 42

• Part of the ~5,000-gold vault haul behind the door whose key was hidden in Halren's ribcage: gold, dead-empire coinage, gemstones, ectoplasm, the deciphering tablet — and one invisible stone.

Session 44

• Kept, not sold. Thalia strings it in a thorn setting and wears it. The party's running joke is that nobody can tell she is wearing jewellery at all; her own view is that they simply don't know it is there.

Session 55 — opened, and destroyed

• Examined. The gemologist Anita put it through drills, saw blades, sample extraction, water immersion and a hydraulic press across two hours and reported: "I think something is in the stone. Sometimes, but not all the time."
• The experiment. Anita touched a shard of the Autarch to it at the end of 32-foot calipers, with the room in welding masks and the doors shut. At ten inches apart the stone began to give off a heat-haze "sweat" from under the vice, and every observer's vision filled with visual snow — static, flickers, moving colour. On the first tip-to-tip contact it cracked and shattered, its shell clattering across the floor as semi-transparent, blacked-out chunks.
• What came out. An eight-foot silhouette — invisible when looked at directly, visible only in peripheral vision — stood up in the room and looked around, "perceiving, and showing at least 3 out of 7 on the sentient scale." The shard's dim glow flared from about a foot of light to three or five, blasted it, and it went out with a burst of radio static, ceasing to be alive and then ceasing to be. Thalia tried to gather the shell fragments: like touching her own shadow, then a shade of dust, then nothing.
• The real cost, discovered afterwards. Anita's workshop had two desks, two chairs and two of every piece of equipment but the shared tools, and Anita was left holding a locket engraved "to the love of my life" — her own portrait on one side, a painted beach framed around the absence of a person on the other. The stone had taken a person's existence: the expedition's second gemologist, Anita's wife, who no longer exists and never has. Nobody in the world remembers her; only the shape of the hole she left is still there.
• Party history checks found no equivalent hole in The Shattered Coin — with the caveat that Lash is no longer entirely sure who is in the group, and briefly wondered whether Draak existed.
• The lore it opened. Fenric's reading (Arcana 27, History 23): the void is barely a school of magic — no scrolls, no glyphs, no books, no teachers, sitting outside the circle of elements as background noise rather than in it — and it is the domain closest to his own anti-magic, since he destroys magic rather than casting it. Its signature is disappearance, hiding and forgetting; Modify Memory is void-adjacent. Both void things the party has met — this and the ten-thousand-handed symbiote behind Caressa — came from space. See Session 55.

Status: destroyed, unrecoverable. What was inside it is dead.