Sacred 2:The Kobold Building Co.
Talk to Ranger Menteriel to learn of the problem with the Kobold Builders.
Kill the Kobold builders!
The first Kobold Builder is somewhere directly north of the Ranger Menteriel; head in that direction (as nearly as the terrain allows) and kill him when you find him. The second is to the east (and possibly slightly north or south) of the first. The third is north of the second, and the fourth is southwest of the third. To get to the fourth (considering the terrain), it is easier to return to Ranger Menteriel, then head north and northwest. Go up the hill and the builder should be to the northeast – this builder is usually fairly static.
Fantastic! I never believed that you could succeed alone! Now I can tell you the whole truth - two other adventurers have already tried and failed to accomplish this task. One of them managed to flee in time, the other one won't start eating solids again until next week. Here is your reward.