Oblivion:Priory of the Nine (quest)

Quick Walkthrough
This quest only becomes available once you have downloaded the 
Knights of the Nine official plug-in.
# Find the Priory of the Nine and enter the Priory Basement.
# Survive the "test of worth" from the ghosts of the Knights of the Nine.
# Retrieve the Cuirass of the Crusader.
# Get clues on the locations of the other crusader artifacts.
# Collect the next four artifacts.

Detailed Walkthrough
Finding the Priory
thumb|right|"Step forward, adventurer, and face us each in honorable combat."
The Priory of the Nine is located in the West Weald; a marker is added to your map when you read Sir Amiel's journal.  Within the main building of the priory you will find a large symbol on the floor.  Activate it; as long as Sir Amiel's Ring is in your inventory, the floor will drop down to reveal a door to the Priory Basement.  Enter and make your way through to the door to the Priory Undercroft.

The Test of Worth
In the Priory Undercroft you will find the ghost of Sir Amiel.  He informs you that he and the ghosts of the seven other present Knights of the Nine will test your worth in honorable combat before you will be allowed to take the Cuirass of the Crusader.  One by one, you will combat each of the ghostly Knights, Sir Amiel lastly.

The exit from the Undercroft is sealed once this challenge starts, so you should make sure you are well prepared for the challenge before entering the Undercroft.  There is a brief pause between each knight's challenge, which provides a quick opportunity to heal and repair armor, but you are not provided with a chance to truly rest and recover.

When you have defeated them all, you will be allowed to take the Cuirass of the Crusader. You are also given the rank Knight Commander in the Knights of the Nine faction.

The Other Artifacts
Talk to all of the ghosts to learn what they know about the various artifacts and to find out more about the history of the Knights of the Nine.  Four knights in particular have specific information about the location of an artifact:  Talking to each of them will allow you to start a quest to retrieve that item.

Note that while there is technically no prescribed order in which to complete the following quests, there is one subquest that generally must be completed first in order to complete the other (without resorting to custom spells). See the Notes section of The Path of the Righteous quest for more information.

Sir Casimir tells you about the Gauntlets of the Crusader. In the Chapel of Stendarr in Chorrol, because of his deeds, he was cursed and the gauntlets fell from his hands, too heavy for anyone to lift.  This starts the quest Stendarr's Mercy

Sir Ralvas tells you about the Mace of Zenithar.  He failed to complete the challenge of retrieving the Mace from the Chapel of Zenithar in Leyawiin, because he did not have complete faith.  This starts the quest The Path of the Righteous.

Sir Henrik tells you about the Shield of the Crusader.  If you are faithful to the teachings of Julianos you may recover the Shield of the Crusader from Fort Bulwark, which was fortified to keep it secure.  This starts the quest Wisdom of the Ages.

Sir Juncan tells you about the Boots of the Crusader.  The boots are guarded by Kynareth and the priestesses at the shrine to Kynareth west of the Imperial City on the edge of the Great Forest.  This starts the quest Nature's Fury

This quest is not complete until you have collected all four of these artifacts.  At that point, return to the Priory of the Nine, where a new arrival, Lathon, will approach you.  After he has talked to you, this quest will be marked as completed (and the subsequent quest, The Faithful Squire, will have started).

Notes
As you collect the artifacts, talk to the ghost knights for some updated information.  Sir Amiel, Sir Juncan, and Sir Ralvas in particular have new dialogues.
For a slight recommendation regarding an order in which to complete the four subquests, see the Notes section of The Path of the Righteous quest for more information.
Despite being ghosts (and thus, presumably, the souls of the knights), all eight of the knights are considered to be NPCs and thus, their souls can be captured for Grand Souls in Black Soul Gems during the Test of Worth. This provides a "fast" and surefire way for players of any level to acquire eight Grand Souls in Black Soul Gems quickly and efficiently without incurring murder charges, bounty or infamy (especially important while completing the Knights of the Nine main questline). Doing so does not break the quest either, nor any of the quests that follow, meaning you will still be able to interact with their spirits as scripted and complete the Knights of the Nine main questline as intended.
This is in contrast to the wraith of Lord Berich Vlindrel, who, as a wraith, is considered to be a creature and has a leveled soul.
As you complete the side quests, people will show up at the priory to join the new Knights of the Nine.  They will clean up the priory for you (in particular adding a lot of new beds upstairs).
If you defeat any of the ghostly knights while they are demoralized, the other knights will react as if witnessing a murder.

Bugs
 

Journal Entries