Prison of Elders

The Prison of Elders is a three-player cooperative arena activity that was included in the Destiny expansion House of Wolves. It focuses on variety, replay value, and skill in the House of Wolves endgame. It is unlocked after completion of the quest The Kell of Kells.

Gameplay
The Prison of Elders is a level 28 matchmaking activity and consists of five rounds of three waves, each round and wave being random. The final round has a random mini-boss.

Each round will take place in a room that corresponds to an enemy species: Fallen, Hive, Vex, and Cabal. Rounds may also have modifiers enabled. In each wave, enemies spawn and must be eliminated. Some waves have an additional objective, such as defusing mines, destroying mines, or eliminating a target, that must be completed within a time limit. If all members of the fireteam die or if the objective is not completed before time is up, the team must restart that round.

There are no checkpoints in the Prison of Elders. Guardians who quit a Prison of Elders activity before it is completed will not be able to resume where they left off.

Upon completion of the final round, all participating Guardians will be able to access the Treasure Room, which has two loot chests and one large chest which can contain rare rewards. All participating Guardians will be able to open the two loot chests, but the large chest requires a Treasure Key.

Challenges
In addition to the level 28 matchmaking activity, there are three challenge modes that offer greater rewards. Unlike the matchmaking activity, self-respawns are disabled, the rounds and waves are predefined, and players can only receive rewards once every week beginning at the Weekly Reset. The level 32 and level 34 activities rotate each week, but the level 35 activity, Skolas's Revenge, is always available.

The possible challenges are as follows:
 * Broken Legion
 * Cult of the Worm
 * Machine Wrath
 * The Forever Eater
 * Urrox's Grudge
 * Skolas's Revenge

Mini-Bosses

 * Val Aru'un
 * Pilot Servitor
 * Wretched Knight
 * Overmind Minotaur

Challenge Bosses

 * Valus Trau-ug
 * Kaliks Reborn
 * Gulrot, Unclean
 * Urrox, Flame Prince
 * Qodron, Gate Lord
 * Skolas, Kell of Kells

Rewards
Upon completion of a Prison of Elders activity, all participating Guardians will be able to access the Queen's Crystal Barrows, also known as the Treasure Room, which contains two small loot chests and one large loot chest called the Queen's Chest.

Killing the boss of a level 34 or level 35 challenge mode has a chance to award the quest The Elder Cipher.

Weekly
Weekly Challenge rewards can only be earned once per week per Challenge activity beginning at the Weekly Reset. Each activity has its own set of rewards independent of the other activities. Weekly rewards are awarded to the fireteam as soon as a Guardian opens one of the small loot chests.

Level 32

 * House of Judgment +200
 * 1 Armor Core

Level 34

 * House of Judgment +300
 * 1 Weapon Core
 * 1 Etheric Light

Level 35

 * House of Judgment +500
 * 1 Armor Core
 * 1 Weapon Core
 * 1 Etheric Light

Small Loot Chests
The small loot chests can be opened each time a Guardian completes a Prison of Elders run. There is no limit these number of chests can be opened per week. A loot chest has a chance to award one of the following:


 * Motes of Light
 * Strange Coins
 * Resources
 * Treasure Key

Queen's Chest
The Queen's Chest will only give rewards if the Guardian possesses a Treasure Key. Upon interacting with the chest, one Treasure Key will be deducted from the Guardian's inventory. There is no limit these number of chests can be opened per week.


 * 1 random Queen's Wrath weapon:
 * Her Right Hand, Legendary Auto Rifle
 * Payment VI, Legendary Pulse Rifle
 * Hygiea Noblesse, Legendary Scout Rifle
 * Her Mercy, Legendary Hand Cannon
 * Her Courtesy, Legendary Shotgun
 * Her Benevolence, Legendary Sniper Rifle
 * Techeun Force, Legendary Fusion Rifle
 * Wolves' Bane, Legendary Machine Gun
 * The Dreamwaker, Legendary Rocket Launcher
 * A chance for an exotic weapon or armor
 * Skolas's Revenge only:
 * Hildian Seeker jumpship
 * Kellbreaker emblem

Variks
Armor Cores and Weapon Cores earned from completing arena challenges can be used to purchase Prison of Elders armor and weapons from Variks, the Loyal. See here for available merchandise.

Skolas
Immediately upon killing Skolas, the following rewards have a chance to drop once per week per character:


 * Wolfslayer's Claw II
 * Wolves' Leash II
 * Aegis of the Kell II
 * Six Dreg Pride II

Trivia

 * Completing an Prison of Elders activity unlocks the Raid trophy/achievement.