Go back up the stairs and pick up the Witch's cat, the cat should be wandering out on the bridges and platforms northwest of her house. The Witch's house is the most south-eastern platform.
Use the cat on the Witch's door.
Open the door to the Witch's house
Search the chest in her house for a few items, note the book.
Kill the three demons west of the Witch and take their amulets.
Open the chest north of the middle demon. Pour the liquid on the doll.
Return downstairs and talk to Klank the dwarf, taking his gauntlets.
Take the bucket in the large house. Use it on the barrel in the small room.
Run east to a tomb in the corner room and use the brew on the tomb. Light it to obtain Iban's ashes.
Use the ashes on the doll.
Run to the north east corner, kill Kalrag the spider.
Go to the north western corner and ascend the stairs to the half soulless area.
Walk south to the third walkway and cross the bridge. Walk north to the first cage, then walk east to the next cage. Walk a little north then west from here to the cage containing Iban's dove (lowest platform in the centre of several others). Wear Klank's gauntlets and search the cage to find Iban's dove.
Use the dove on the doll.
Make way to the middle of the the cavern maze and kill a Disciple of Iban, grab his robes.
Un-equip everything and equip the robes. You don't need planks or rope any more.
After Iban is destroyed if you don't have 2 free inventory spaces 15 Death Runes and 30 Fire Runes will be dropped under you.