The Train Route
To begin, go to the northern part of Dorgesh-Kaan, climb up the stairs, head east, and speak to Ur-Tag. They will tell you that they have plans to build a train route from Dorgesh-Kaan to Keldagrim.
Head to the south west side of the city, where you will find a doorway. Go through this, and you will end up at a train station. Walk down the tracks, and speak to Tegdak. He will give you a trowel and a specimen brush. Use the trowel on the artifacts that are hidden under the floor. There are 6 total artifacts; two north of the tables, and four south. Clean all six artifacts on the specimen table, then speak to Tegdak again.
Go to the Goblin scribe (with Zanik!), located at the same place you began the quest. Ask him about the symbols that are on the mace you dug up. He is not able to tell you anything, but he tells you to speak with the goblin generals in Goblin Village.
Speak to Oldak, who is west and down the stairs from the scribe. Oldak will teleport you to Goblin Village, and give you a sphere to return to Dorgash-Kaan. After you teleport, speak to one of the generals, and a cut scene will begin. You will learn that Zanik is the "chosen one" and the mace is the power of the Goblin God.
Two H.A.M. members will show up, and will begin to attack the goblins. Go around the back (to the west) and climb up the tower ladder. Kill the H.A.M. ranger and mage using ranged or mage. (There is a bronze crossbow and 50 bolts by the crates you cause use if you wish)
After you have defeated them, you will watch a cutscene that shows Zanik getting kidnapped by Sigmund. The generals will tell you to meet two sergeants in the Lumbridge Swamp Caves. They will also give you the Ancient Mace.
Sigmund plans to kill Zanik on the train tracks, making it look like an accident. Head to Lumbridge Swamp and speak to one of the sergeants. They are located at the entrance to the swamp. Climb down, into the caves and go down the ladder next to the rope. You will see a H.A.M. guard run away to get reinforcements. Run down the hall and talk to the goblins. Tell one goblin to hide, by going into the room to the east. Run up to the boxes to see another guard come out. Tell the other goblin to wait there, then go back to the first room. Run past them, towards the ladder, then run back towards the guard so he gets sight of a goblin, then head down the ladder.
Note: If you are spotted by a guard, quickly run to a goblin
After you have gone down the ladder, you will notice Zanik tied the the railroad tracks. Attack Sigmund using any method, and he will turn on his prayer. Wield the Ancient Mace and use the special attack. This will make all of Sigmund's prayer points drain to 0. Now continue to attack him until he dies. Do NOT try to untie Zanik before defeating Sigmund.
He will teleport away after being defeated, leaving you to untie Zanik. Congratulations! Quest Complete!