In Perfect World, as well as players and monsters, there are also NPCs or Non-Player Characters. You can interact with these characters for quests, to gain new skills, learn game information, and to buy, sell, manufacture, decompose, identify, and upgrade items.
There are many different types of NPCs. Some types are:
Adventure Assistant and Khatru Pup
Craftsmen, Apothecaries, Tailors, Blacksmiths, and Merchants
Faction Base Manager
Messenger of the Sages
There are also other NPCs that will give quests as you level up that have no other purpose, e.g. Aroma in Archosaur, Ladywraith near Orchid Temple, and many others.