Most of the NPCs of this game are part of a Quest, even if you need to talk to them just once. They can be part of a big Quest with many NPCs involved, or can be the single NPC such as a Daily Quest. These will often give you a reward at the end of the Quest but that isn't always the case.

Tulimshar	Hurnscald	Nivalis	Graveyard	Others
	Alan		Hamond
	Arkim		Thurstan
			Wolfgang