NPC quests
Besides the evolution quests, which change your class, there is a second system: NPC quests with dialogue, which pay zen and experience.
Who gives them
The Shadow Phantom Soldier. He is spread across the towns — Lorencia, Devias, Noria, Elbeland and Arena.
Requires level 50.
How it works
Talk to him and he talks back. Each quest asks for one thing — kill a number of a certain monster, or bring an item — and when you come back, he pays and opens the next one.
It is a chain: one quest unlocks the following one.
What it pays
Zen and experience. No items.
The experience is useful early on, and the zen is what serves most — it is money without depending on drop luck, and money is what raises items.