Black Myth Wukong quests are rarely straightforward, and you usually have to search for a while before you find where to go. This is especially true for the Treasure Hunter quest. Here is the solution for each step of his quest.
Save the Treasure Hunter
The first stage requires you to cross the bitter lake on the back of the giant turtle. Once the Altar on the beach is activated, go to the left of the area. A group of harpies are attacking a poor defenseless human being. Just kill them, then talk to him, before moving on.
How to warm up the Treasure Hunter?
The next step awaits you in the Valley of Ecstasy, at the Altar of the Forest of Bliss. The Hunter is on the left side of the area, on the pedestal of a statue. He is dying of cold, and is asking for fire to warm himself. This is good, since the old Chinese master should have taught you how to summon a Circle of fire.
Return to the nearest altar, changing your spells if necessary. Then, summon the Circle of Fire near the Treasure Hunter. He will thank you, before giving you clues on the location of a strange melon field at the foot of a cliff.
Where to find the Melon Field?
Once again, start from the Valley of Ecstasy, at the Altar of the Forest of Bliss. This time, head to the right of the area. Cross the pond shown in the image below.
Approach the corner on the right, you will see several enemies near the braziers. After killing them, you will be able to go down the cliff.
The rest is simple, go down along the cliff, until you reach the altar of the Melon Field.
Green-Hat Martialist Boss
After activating the altar, enter the nearby cave. The Treasure Hunter will appear, before revealing his true identity, the Green-Hat Martialist. He will then attack you with his flaming spinning chakram. Having consumables against fire can be useful.
What makes this boss annoying is that he is invincible, when his giant chakram is summoned. You are forced to wait, while dodging. Towards the end of the fight, he will even summon two at the same time.
Once you’ve won, Little Buddha will reward you with a new power, Spell Binding. It blocks your spells and special abilities, in exchange for an attack bonus.