End Time is a heroic-only dungeon found in Caverns of Time, released in Patch 4.3.0 as part of the progression to the fight against Deathwing. This first instance building up to the fight with the Worldbreaker takes adventurers into one of the many possible futures of Azeroth, revealing what will transpire if Deathwing is not stopped: theHour of Twilight.
Caverns of Time, Tanaris(entrance)
Dungeon - Heroic
You will encounter three bosses in this dungeon, the first two being randomly selected out of this list of bosses:
Echo of Baine - Obsidian Dragonshrine
Echo of Jaina - Azure Dragonshrine
Echo of Sylvanas - Ruby Dragonshrine
Echo of Tyrande - Emerald Dragonshrine
The dragonshrines, as well as the starting point are accessed via transportation devices. Nozdormu in his humanoid form can be found hovering near it. After defeating two of fallen heroes, the party faces off Murozond as the final boss in the Bronze Dragonshrine.
End Time is a dungeon added in Patch 4.3, Hour of Twilight. Players aid Nozdormu in righting the past and observing darker versions of history. Select faction leaders are corrupted and residing in destroyed dragonshrines--you will encounter two of the four in each dungeon before facing the final boss, Murozond.
As the bosses drop ilvl 378 loot, this dungeon is more challenging than other heroics and requires ilvl 353 to queue.
From the Blizzard Community site:
"One of an infinite number of potential outcomes, this timeway depicts the desolate future of Azeroth should Deathwing fail to be stopped. Nozdormu has identified a powerful anomaly that exists in this moment and bars access to the past - and hope of retrieving the Demon Soul. A powerful creature from out of time living alone amist time-twisted echos of the past."
Required item level: 353
Instance type: Dungeon
Heroic mode available (85)
Number of players: 5
Final boss: Murozond
Echo of Tyrande ¨C Once the leader of the night elves and High Priestess of Elune, this time-twisted fragment of Tyrande Whisperwind now wanders the wastes of the desolate future of Azeroth. Enveloped in a perpetual midnight, she has all but lost sight of the comforting light of Elune.
Echo of Jaina ¨C The tormented fragment of Jaina Proudmoore has been split and infused within the shattered pieces of her staff. To restore balance to the timeways, this echo must be defeated. However, the devastating magical power possessed by the once-proud ruler of Theramore is hardly lost to her time-havocked spectre. In this future Azeroth, she is only divided, and waiting...
Murozond ¨C Now living outside of time, Murozond was once the great Dragon Aspect Nozdormu the Timeless One. After the titans showed him his own death, the tormented Nozdormu was tricked by the Old Gods into trying to subvert his mortality. As a result, Nozdormu shattered the timeways and created the Infinite Dragonflight... jeopardizing the very future of Azeroth.
Echo of Sylvanas ¨C Spawned from shattered timeways and cloistered within the Ruby Dragonshrine, a maddened fragment of the Forsaken's leader, Sylvanas Windrunner, waits restlessly. Having lost everything and unable to find peace, this tormented echo aches for a chance to unleash her dark fury at anything still living within these barren, time-twisted wastes.
Echo of Baine ¨C Enraged by his failure to protect the world and, most importantly, the Horde, this time-ravaged shade of Baine Bloodhoof lingers within the ruins of the Obsidian Dragonshrine. Although he's still as powerful as the tauren high chieftain from the present, within this shattered future Azeroth, this guilt-ridden echo is little more than a discordant vessel of unquenchable malice and anger.