This quest becomes available starting in Chapter 4.
Speak to the Trader at Castle Gate Plaza and gather the items he requests.
Pocket Watch: Copper, Iron. Reward: Light of the Outsider
Silk Dress: Silk x10, Fur x10. Reward: Ogre Nail
Mofu-mofu bag: Fur x10, Diamond x3. Reward: Reptid Fang
The last two requests become available after Chapter 27.
This is a repeatable quest.