- Level: 70+
- # of Players: 25
- Location: Caverns of Time
- Abbreviation: Hyjal, HY, HYJ
- Final Boss: Archimonde
- Released: Burning Crusade
- Reputation: Friendly with the Scale of the Sands
Template:CoT Blizzard has announced that one of the new locations in Burning Crusade, the upcoming expansion to World of Warcraft, will be the Caverns of Time, where players will get to travel to past events in the Warcraft universe, one of which is the Battle of Mount Hyjal. Players will get to join the last stand against the Burning Legion at the end of Warcraft III and fight Archimonde and his forces as they make their way up the slopes of Hyjal.
Oddly enough, although the quest NPCs involved in getting attuned for the Caverns of Time mention that the Battle of Mount Hyjal is a timeway that is being deeply disrupted by the Infinite Dragonflight, who are working tirelessly to keep it a secret from the Bronze dragons, there is not a single Infinite Dragonflight member in the instance; unlike the other two Caverns of Time instances.
Drysc about the Battle for Mount Hyjal:
- "It's a "time pocket" if you will. There's no intended link to the Infinite Dragonflight or their dastardly deeds of altered timeways, and you're not literally interacting with history. It's simply a way for players to experience some of the larger moments in Warcraft history, and admittedly the Mount Hyjal instance isn't really linked to the world for any rhyme or reason. The timeway presented itself, it's an amazing opportunity to be there and experience such a major event, and Archimonde drops phat purples." 
- "The Caverns of Time are a strange and complex place, and I don't suspect we will ever be able to fully understand the complex goings on inside them." 
Like many raid instances, the Battle of Mount Hyjal requires players to be attuned to the instance before entering it. Upon reaching level 70, talk to Soridormi, the consort of Nozdormu. She will give you a quest named The Vials of Eternity. This quest requires you to defeat Lady Vashj in Serpentshrine Cavern and Kael'thas in the Eye of Tempest Keep and retrieve the Vials of Eternity from them. Upon completing the quest, you will be attuned to Mt. Hyjal. Both Serpentshrine Cavern and the Eye no longer require attunement as of Patch 2.1.2.
Each boss (except Archimonde) has 8 different trash waves which can consist of any of these mob types.
The Battle of Mount Hyjal
This instance intentionally mirrors the last level of Warcraft 3, Battle of Mount Hyjal. The units wear the same clothes they had in Warcraft 3. For instance, Horde Shamans wear the same wolf-like fur on their heads. The events begin in the Alliance base. Jaina herself is in the base, with a small army of Alliance NPCs, Footmen, Riflemen, Knights, Priests, and Sorceresses. The raid has to face eight waves of elite undead, such as Ghouls, Crypt fiends or Abominations. Units have exactly the same abilities they had in Warcraft 3, such as Cannibalize for Ghouls, Disease aura for Abominations or Brilliance Aura for Jaina. After 8 waves, the first boss comes: the lich Rage Winterchill, who was already present in Warcraft 3. The waves are on timer, so the raid has to destroy the undead before the next wave attacks. If the raid wipes on Winterchill, you will have to kill all the waves again, but once Winterchill is dead, he will be considered dead if the raid wipes later - just like in Serpentshrine Cavern or any other instance. Speak to Jaina to begin the second part of the Alliance Base encounter. There are several more waves of trash to defeat before the arrival of the second boss, the dreadlord Anetheron. Once Anetheron is taken down, the Alliance forces are defeated and the raid now moves to the orc base.
Just like Jaina did, Thrall assists you in person and with several Horde NPCs: Grunts, Headhunters, Shamans, Tauren. The Undead Scourge and the Burning Legion keeps sending necromancers, banshees, gargoyles, infernals or even frost wyrms against the defenders of Azeroth. The first boss will be Kaz'rogal (which was not present in Warcraft 3), and, after several more waves, the last lieutenant of the Burning Legion will be the pit lord commander Azgalor.
Once again, the base falls, and the raid have now to help the last defenders of the world, Tyrande Whisperwind and her Sentinels: Archers, Huntresses, Druids of the Claw, and Druids of the Talon. After a few more assaults of the demon/undead army, the raid will have to face the master of the Burning Legion, Archimonde. Eventually, a huge group of wisps attack Archimonde directly and detonate, destroying once and for all the mighty demon lord.
- See The Burning Crusade: Guild Progression for the world first kills