I see a Courier on the road, he sees a troll of the side of the road and proceeds to attack it with his iron dagger. Then a nearby Reveler (one of those Nords offering you Honningbrew) moves in with his fists. I decide to try and save them. I kill the troll, but the courier died during the fight. Curious, I search his body. What do I find?

A book: 'Slaying Trolls.' I [censored] love Skyrim.

Wait a sec, aren't couriers essential NPCs?

Not the ones you see on the road, apparently. He didn't have a message for me.

M'aiq wonders if you saw him when you were wandering the wilderness..

That's pretty good if it's true.

There are two types of couriers: the ones who deliver letters to us and the ones spawned by World Interactions. The first is essential, the second is not.

HAHA. I'd believe it.

I've come across bathrooms in bandit/imperial forts with a lusty argonian maid book by the bucket and a bottle of two-handed or true shot next to it.

And yes there are npcs in the world delivering messages. What you think your the only special one in Skyrim? Sometimes they do have letters if I recall. But never anything that amounted to a quest.

I usually kill the courier's just to check if they have any letters on them.

GOLD!!!