The messenger travels from the Jangelode Mine (44, 25), goes into Gold Coast Quarry cave (30, 45) and then goes down to Moonbrook (43, 69)

You have to kill him to get the follow up quests from Sentinel Hill

As has been noted, he spawns in Moonbrook, east of the fountain, just before the road turns north. He then walks along the Old Coast Road until he gets near the Gold Coast Quarry, then runs down the ravine into the Quarry to a spot fairly far in, but not the very back. This is one of the two times he runs, the other being when low on health. And yes, he hauls butt, even when critical.

Anyways, after that he walks back out and up the road to the Jangolode mine, and into the back of there and back out. Time spent in the Quarry is less than 2 minutes, in the Mine a bit upwards of 3. Assuming he hasn't died yet, he then ambles back south down the same route he took up, until a point somewhere between Moonbrook and the Quarry. At this point he seemed to just be travelling back and forth over a small section of road, until someone came up and killed him. I'd been tracking him for more spawns than I care to recall, so I stopped at that point. Oh, the respawn time is about 4 and a half minutes, usually.

He's fairly easy to kill, nothing special about him. But feel free to group with anyone else with the quest, everyone in the group that kills him will be able to loot the message. The respawn is short, but why waste the time?

Edit: Just occured to me, he won't attack you on sight. You can walk right next to him, and he'll ignore you. I'm pretty sure he won't even assist other Defias, but I could be wrong.

Edited, Sun Feb 27 22:06:22 2005

He spawns at 44,69.

He spawns at 44,69 next to this barrel or jug on the ground.. but he like to run once you hit him, so make sure you clear the area, hes spawn time is pretty fast