In order to complete this quest you will need the following: A Rope, and at least 48 in 'pursuade' skill. NOTE: Having 'Mark' and 'Recall' spells will save you a HUGE amount of time travelling between Eldfell and Thule during this quest. Create a Mark in Eldfell city centre, and a Mark at the Abbey of Thule. Here's the guide by Michele_L
You'll need to find your way to the Abbey of Thule in the southwest of the Island of ice.
Once you reach Thule Abbey, you will need to go to the small wooden door to the right of the large gates. The guard there will give you the key to the large gates.
Find and talk to the Abbot and talk to him. You'll learn about brother Joffrey being murdered. You need to ask about checking out brother Joffrey's room for clues.
Brother Joffrey's room is along the corridor of the Abbey on the west side. Go inside and find the goblet on the shelf. Take it to Brother Joram in the gardens outside of the Abbey (to the west - bring up world map to see). Brother Joram will tell you there is hemlock poison inside the goblet.
Find and talk to Sister Pamfila (You'll need 48+ persuade) to find your next clue - Father Benedetto. Sister Pamfila can be found in the green colored building in the middle area of the Abbey.
Find and talk to Father Benedetto (The man out by the cemetery of Thule) He will tell you to make sure you've checked brother Joffrey's room good enough for clues.
Go to brother Joffrey's room and you'll find his journal behind the green painting. (It's to the left of the shelf where you found the poisoned goblet)
Read the journal.
Talk to the Abbot about what was written in brother Joffrey's journal. The Abbot will tell you that he's going to his secret library. Tap the east wall in the Abbot's room until it opens to his secret library. Tap all of the ladders that you see until you find the Abbot’s journal.
Read the journal.
You'll find the Scorpion Flail for brother Jago on a shelf here.
Find the boy Daku walking around (Daytime only) inside the northeast corridor surrounding the Abbey. (Not the boy Celso in the center of the Abbey) Talk to him about doing the errand for the Abbot.
Go to the Ankle of Thule - west shore area and find Shusanna's house. (South of the garden and west of the cemetery) Talk to Shusanna. She will tell you about her child that was brought to the Home of Unwanted Children. It's the northern part of Eldfell City. (The door on the west side just before you exit the city) Talk to Hartwin.
After talking to Hartwin, you need to find and talk to Father Valar at the Church of the Poor in Shacktown. (East of Eldfell City). Valar will give you Hartwin's journal.
Read the journal.
Go back to the Abbey of Thule and talk to the Abbot again. He will give you the key for the Cult door. (In the basement of the Abbey) Talk to the cult leader about the Beast.
Go to the governor of Eldfell and talk to him about the Beast. Go back to the Abbot's room. You'll find Boad the Beast there. Talk to him. He will infect you with flesh eater's disease. You'll be transported to an area where Solfecht is. Talk to him. Find and talk to Brother Alvaro in the basement of the abbey to get cure flesh eater potion. Talk to him again and ask him about the Abbot's location. He will tell you the Abbot was heading to the cemetery.
Go to the crypt of Thule to find him. Talk to the Abbot about the Beast. A secret passage will open, in the south eastern area of the crypt.
You'll need a rope in this area to get across a gap in the floor.
When you reach the door of the Beast's lair, turn to the left and look for a crack in the wall. Hit it and look inside for the Sword of God. Open the gate and kill the Beast.
You'll find the Redshift Hammer here.
Go back and talk to the Abbot (he's still in the crypt). He will give you the keys to the Abbey. Talk to Brother Joram who is still in the gardens to the west, and give him the sword and keys.
Go to Eldfell and talk to the Governor about the situation on Thule. After choosing to speak "it's over",
If you told the Abbot you would kill the Governor,He will lock you out of the room and you will face a number of powerful enemies/bodygaurds. (having a high 'resistance' spell helps greatly).
If you told the Abbot you would kill him and side with the Governor, the Governor gives you the Executioners Axe and the Maul of a new Age. Use the maul on the Eldfell(Fire island) side of the bridge to allow the flesh eaters to overtake the island.
If you got the Maul of Healing from the Abbot, use it on the Thule (Ice Island) side of the bridge to once again link the islands.
Return to Brother Joram in the Abbey Gardens and tell him about the Abbot's confession.
The Find Brother Joffrey's murderer quest has been solved.
Your fame is increased and you receive 500 experience and your health is temperately increased by 100.
You Have now completed the quest!