How to make wild knives with Tianmu?

The Tianmu Eagle needs to reach Tao Ren Island first, climb to the top of the island, and you will see a man in a cage. Save him. He will tell you to find four stone slabs through which you can find the treasure. After getting all the slates, go to Daolian Island to talk to NPC. When you find yourself cheated, go to Putian Village to find NPC to get the sword painting of Tianmu Eagle.

The way to obtain Tianmu Eagle Knife is to complete the task of the rice wife world, get the drawings after the farmer's treasure, and then go to the blacksmith's shop for forging. There is no obvious hint in this task. Deciphering the key prop slate runs through other side missions and world exploration.