Starting the Quest
Speak to King Lathas on the second floor of his castle.
High Agility (At least 50 recommended, 70 is preferred)
50 Thieving (for a shortcut)
Rope (2+ recommended)
Equipment for dealing with high-level monsters
Food is highly recommended. Bring as much as you can carry. (If you run out, you can get more in the dungeon.)
This is one of the longer quests /v/scape has to offer. It will take a while to complete, at the very least 40 minutes. To get started, talk to King Lathas. Make sure you have all your gear, and head into West Ardougne and head west until you reach a cave entrance. Talk to Koftik and head inside.
Getting Across the Bridge
Now that you're inside the cave, you'll see three paths ahead of you. DO NOT TAKE THE MIDDLE ONE. Climb over the rocks to take either the north or south passage. You will come to a bridge. Talk to Koftik again, and he will give you a damp cloth. Use the cloth on your arrows, and use the wrapped arrow on the fire. Equip the lit arrow and your bow, and click on the guide rope. A short cutscene will play and you will be across the bridge. You may notice a lever after crossing the bridge. Do not pull it, or you will have to shoot the guide rope on the bridge again. Continue down the hallway, and you will reach a pit. Use your rope on the overhang, and continue down the hallway.
Soon you will reach a large mesh in the floor. Talk to Koftik again, and cross the mesh. The path across it is randomized and sometimes you will fall into a spiked pit. This will deal a large amount of damage. Keep trying until you reach the far side. Pull the lever and run through the gate.
The Orbs and the Well
After the grid, continue along the path. Pay attention to the walls, as some of them have traps on them. You can attempt to disarm them, or run through them for minor damage. You will come to a small cove with an altar and a well in it. There is a journal you can pick up and read for flavor reasons, but it is not needed. Do not try to climb down the well yet. Your objective here is to collect four orbs located at the ends of the various branching pants.
The four paths are:
1) The north one. This path has some pressure pads along the way. You can attempt to disarm them, run over them for minor damage, or use your plank to safely cross them. Reach the end and grab the orb.
2)The northwest one. Very simple, avoid the monsters and grab the orb.
3)The west one. Just like the north one, reach the end, grab the orb.
4) The southwest one. This one seems safe, but if you try to pick it up a trap will damage you. Right click on the orb, and disarm the trap underneath the orb. You can now safely grab it.
Now that you have all four orbs, head back down the path to where the furnace was. Chuck all four orbs into the furnace, and now you can head down the well.
The Cages and Obstacle Maze
If you're running low on food, search the nearby crates for some salmon and meat pies. If you need some rope for whatever reason, there's a spawn in the little alcove to the northwest. Continue down the hall until you reach some cages. Enter the first one on the left, and use your spade on the mud hole. Continue onwards, and cross the ledge. There are two paths you can take now:
1) If you don't have 50 thieving, you will have to cross a stone bridge, and there is a possibility of failing to cross and getting hurt. Continue until you reach the end of the bridge.
2) If you have 50 or more thieving, head as far south as you can from the ledge. There will be a door you can pick the lock on.
After passing this, continue into the entrance.
The Caged Unicorn and the Paladins
For the next step, you'll need the unicorn's horn, but you can't quite get it since the unicorn is locked away. This is what the unicorn deserves. Search the cage to get a piece of railing. Next, go up the path next to the cage, and use the railing bit on the rock. Search the wreckage to obtain the unicorn horn.
Continuing onwards, avoid the monsters until you reach three paladins. (If you talk to Sir Jerro before killing him, he gives 2x bread and 1x stew) Kill the three and take their badges. Head west and avoid the traps, until you reach a well. Throw the unicorn horn and three badges down the well, then head through the door.
Now you're in the most FUN area of the Underground Pass. Head as far south as you can, and then west a little until you reach some stairs. Head down and head west, and talk to the dwarves there. If you're running low on food, Kamen will give you unlimited food (however you will take a small amount of damage and lose 3 levels of agility every time you receive some.)
The next step is to receive Bane's mask Iban's doll. Head east and then north a little until you reach the first path over the abyss. Jump over the broken section (there is a possibility you will miss the jump and fall down below. If this happens, head south and go back up the stairs.) After reaching the platform, head south and you'll see a house. Do not open the door. Instead, click on the window - note that a message about her looking for something will show in your chat interface, and that's it, not a conversation. From here, head back to the platform, then head west to a second one. Head north from there to a third, then west to a fourth, and then north once more to a fifth. The cat should be there. Pick up the cat and return to the house. Use the cat on the door, and now you can get inside the house. Search the witch's chest to get some potions, a book, and Iban's doll.
This part requires you to get four elements to imbue the doll with. They can be done in any order.
1) Iban's Shadow. Head back to the first platform, go west to the second, then head south. There should be three large platforms with demons on them. You must kill the demons and take the three amulets they drop. Head back to Doomion's platform, and head north. Use the amulets on the chest, and use Iban's shadow on the doll.
2) Iban's Body. Head back down to where the dwarves are. Talk to Klank. He should give you some gauntlets (hold on to these. You don't need them right now, though.) Use your bucket on one of the barrels inside the house to get some dwarf brew. Head to the southeast corner of the cavern and you'll come upon Iban's tomb. Use the brew on the tomb and them use the tinderbox. You will get Iban's ashes. Smear them on the doll.
3) Iban's Blood. Head directly north from the tomb until you come upon a large amount of blessed spiders. Ignore them and continue deeper into Spiderland. At the end, kill Kalrag, and you will automatically smear the doll with Iban's blood. The blessed spiders will gang up on you after this, so run out of the cave.
4) Iban's Conscience. After exiting Spiderland, put on Klank's gauntlets and head to the northwest corner of the cave. Go up the stairs. Cross the path and search the cages. One of them will contain Iban's conscience. Once you receive it, use it on the doll.
This is the last step of the quest. Head back to the northeast corner of the cave. Cross the broken path, then head south down the path. Keep taking the south path until you reach the center of the cavern. Kill a disciple and steal his robes. Before fighting the big bad evil Iban, you must be wearing only the robes- nothing else. Enter Iban's room. Your task here is to use the doll on the well, which can be difficult as Iban likes to push you away. Keep trying until you throw that fucker into the well. Iban will die.
After this, take your rewards, head back to King Lathas, and tell him of your success.
5 Quest Points
6750 Agility XP
6750 Attack XP
Ability to use Iban Blast
150 Death runes and 300 fire runes