Rare item in trade with Braiq Crax. Mysterious picture, need to use Clarifying potion, after which a Ichtaca's Secret will appear in your inventory.
Ichtaca's Secret its a note with a hint where to look for treasure. After reading, you need to go to the location Ruined Court in Gathering, and click to the location picture, then in your inventory will appear Macuahuitl (unfinished). To finish it you need Crafting level 85 and 18 units of Obsidian. Then you will receive a weapon Macuahuitl (10 ATK, 110 STR, 3.3s atack speed) as a reward.