Oh. It wasn't a gem. It was a lens.
It was his lens. It was his forbidden knowledge brought back from the Out, plucked from the depths of his soul and placed between him and the figure… as a bargaining piece.
Finally, Hazō understood. The figure wanted his Out lore, or perhaps it simply wanted him not to have it. But for some reason, it couldn't just take it. Instead, in exchange, it was offering him the map–knowledge of Akane's exact location and the lands in between, making for the swiftest, easiest possible rescue.