Mól ring
A bugbear-sized ring of Mól metal, engraved on the inside in G'lin
A tarnished ring, found alone in a stone nook whose other slots had been emptied long before anyone alive got there, which is a fair argument that it was the real prize of that room.
Cleaned up, its sheen turned out to match the gray veining that runs through Mól stonework exactly. That is what settled a question the party had been circling: the metal in the walls and the metal in Mól-made things are one and the same. It tarnishes when it is worn or pressed, though the veins in the walls never do. It is sized for a bugbear, and sits on Koa’s thumb.
The engraving is on the inside, where only the wearer would see it, and it is G’lin, possibly an archaic dialect of it, which may put it beyond even the hobgoblins of Draazstone. Nobody has translated it.
Aldo wore it into the keep’s lock, where Mól metal is the thing that carries the charge. What became of it after that was never written down.