Kulau's Obsidian Crook

Kulau's crook is an obsidian weapon that is usually stored as a small obsidian gem, but either impacted on the ground or flicked with his claw it unfolds into a crook. Not only does he use it to manipulate his surroundings in combat but also uses it as a catalyst for his magic.

He's taking it with him because it is incredibly useful in combat, and magnifies his powers. But he's also taking it because it's a mystery to him, and ties him to Covillayne, who has the other half of the stone.