The Mage's Treasure

This optional side quest can be obtained while exploring the Brecilian Forest, and leads The Warden to gather all of the pieces of the Juggernaut Armor Set

Tombstones
Throughout the Brecilian Forest, the Warden will come across certain Tombstones, or Gravestones. Each can be inspected, and then activated by disturbing the wards on them. In each case, a Revenant will spawn and attack the group, often aided by minor undeads (Skeletons, Skeleton Archers, Fanged Skeletons and/or Skeleton Mages). The Warden will find a piece of the armor set after winning each of these fights. Note: To be able to activate this quest you will (in most cases) need to start with the Northern Ancient Tombstone in the East Brecilian Forest, otherwise you will not see the "Disturb the wards" option in your dialog.

The location of the tombstones: Note: You can watch this video for a tutorial.
 * West Brecilian Forest: a clearing in the Eastern part of the area, past the encounter with Swiftrunner and North of The Grand Oak:
 * Defeating the spirit at this location yields the Juggernaut Helm;
 * Note The Gravestone at this location is particular for a couple of reasons:
 * The Warden can inspect this gravestone but the option to disturb its wards is not available until the quest is acquired by activating one of the other tombstones associated with this quest;
 * A Mystical Site of Power landmark is found in this same location, associated with the Places of Power quest;
 * East Brecilian Forest: a clearing in the North portion of the map, close to the clearing where the Mad Hermit is found (see Northern Ancient Tombstone):
 * Defeating the spirit at this location will yield the Juggernaut Plate Boots;
 * East Brecilian Forest: a clearing in the South portion of the map, past The Magical Barrier, right after the second encounter with Swiftrunner (see Southern Ancient Tombstone):
 * Defeating the spirit at this location yields the Juggernaut Plate Gloves;
 * A Sarcophagus within The Elven Tombs (specifically, in the Lower Ruins):
 * Defeating the spirit at this location yields the Juggernaut Plate Armor
 * See below further details about this last location.

The Elven Ritual
The last piece of the armor set is found in the Lower Ruins level of The Elven Tombs. In order to disturb the spirit holding the last piece of armor, the Warden has to complete The Elven Ritual quest. As the Warden enters a large room with a circular mosaic on the floor, the spirit of a Ghostly Boy will call out for his mother. The Warden can try and talk to him, but he doesn't seem to hear or understand the Warden, and will flee away.

In a side room close-by, the Warden can retrieve A Carved Elven Tablet from a Sarcophagus, which will add The Elven Ritual quest to the journal: (It is located in the square room, directly south of where you found the ghost boy and fought the skeletons. Now from here, go back into the ghost boy's room and head right down the hall, making the first available left, go down the stairs on either side of the large tree roots and there is the fountain. The alter is to the left.)

With the quest in the journal, and the tablet in the inventory, the Warden can proceed to the large room in the North-East corner of the Lower Ruins. A locked Metal Door will stop the party in a room with a Fountain (or pool) in the middle of another rounded mosaic, and an Altar on the side. This altar might not be there, which would make it impossible to complete the quest and obtain the Juggernaut Plate Armor

The Warden can perform the ritual as described by the tablet in this room:
 * 1) Take the earthen jug from the fountain.
 * 2) Fill the earthen jug with water.
 * 3) Leave the pool alone.
 * 4) Place the filled earthen jug on top of the nearby altar.
 * 5) Kneel before the altar and pray.
 * 6) Examine the earthen jug on the altar.
 * 7) Take a single sip from the water in the earthen jug
 * 8) Take the earthen jug.
 * 9) Leave the altar alone.
 * 10) Dump the remaining water from the earthen jug into the fountain.

If the Warden makes any mistake in the sequence, two Shades will attack the party. On the other hand, the jug will not break and the Warden can try again. When the Ritual is completed successfully, the jug will break, The Elven Ritual quest is completed and the Metal Door will open, allowing entrance into the Elven Burial Chamber.

The Warden will have to fight a group of Skeleton Archers to reach the spirit in the middle of this large room, who appears to be the Spirit of the Ghostly Boy's Mother. However the Spirit will quickly turn against the Warden, summoning a couple of Greater Shades to aid her. When the fight is over, the Warden can inspect the Sarcophagus atop the stairs and retrieve the last piece of the Armor set (and discover the Codex Entry: Uthenera).