Before the Burning Legion was about to strike at Azeroth from Outland, Kruul was tasked to kill Illidan Stormrage. The two battled but Kruul was eventually defeated and left the fight through a portal.
When the defenders of Azeroth pushed the demonic forces back through the Dark Portal to Hellfire Peninsula, Kruul joined his forces at the Stair of Destiny to fight them. Unbeknownst to the Azerothian forces, Kruul was attacked by Illidari demon hunters who distracted him long enough for 伊利丹·怒风 to kill him with a blast of fel magic that tore a hole through his torso. Without Kruul to command them the demons fell into disarray, allowing the Alliance and Horde to gain a foothold at the Stair of Destiny. They would never learn that the Illidari had saved them from certain defeat at the hands of Kruul.
Soon after Kruul's death at the hands of the Illidari, the Illidari were imprisoned by the Wardens. During that imprisonment, the 肯瑞托 locked Kruul's heart away in the vaults of 达拉然 to keep the Legion from retrieving it. Many years later, during the Legion's third invasion of Azeroth, the demons finally broke into Dalaran's vaults and stole Kruul's heart despite Kor'vas Bloodthorn's attempts to stop them. Prophet Velen discovered that Kruul's minions stole his heart to hasten his return within the Twisting Nether, and sent Kor'vas and an adventurer to the Stair of Destiny to pry open a way into Kruul's realm.
Kor'vas worked to reactivate the portal that Kruul's lackeys had left behind, while defended by the adventurer from demons that were trying to stave them off while Kruul was regenerating. After the death of Lord Vazuun, Kor'vas decided that the two of them could not defeat Kruul alone and sent the adventurer back to Dalaran to report to the Council of Six while she kept the portal stabilized. Archmage Modera vowed to prepare an assault on his lair, and Archmage Karlain ensured that the Illidari were given all the supplies that Dalaran could spare.
Later, the adventurer, Kor'vas, and Velen confronted Kruul inside the Twisting Nether. He claimed to be empowered by the souls of a thousand conquered worlds and killed most of his own minions to empower himself further. Inquisitor Variss captured Kor'vas, but after Velen and the adventurer killed him to free her, Kruul attacked. Before he could die Kruul overloaded himself with power to self-destruct and kill his opponents along with him, but Velen saved Kor'vas and the adventurer. Because he died inside the Twisting Nether, Kruul is now dead for good.
From the World of Warcraft news page under patch 2.0.3:
It is also reported that Lord Kazzak was seen departing through the Dark Portal. In his stead he has left his minion, Highlord Kruul, to sow fear and confusion among the defenders.
Accompanied by a host of 地狱火s, Kruul has been seen near a number of major cities in Azeroth (a possible reference to the near legendary kites of his predecessor Doom Lord Kazzak), along with the following outdoor areas:
- Azeroth has cowered too long under our shadow! Now, feel the power of the Burning Crusade, and despair!
- Your fate is sealed, Azeroth! I will find the Aspect Shards, and then you will not stand against our might!
- Cower, little worms! Your heroes are nothing! Your saviors will be our first feast!
- Where? Where are the Shards! You cannot hide them from us!
- Your world will die, mortals! Your doom is now at hand!
Killing a player:
- Your own strength feeds me, <player>!
- Ha! This place is not yet worthy of my infliction.
- Although Highlord Kruul is said to have "replaced Lord Kazzak", he disappeared from the game after the end of the world event Dark Portal Opens.
- When Illidan and his demon hunters fought Kruul in World of Warcraft: Illidan, he used several of his in-game abilities.
- Kruul was orange in The Burning Crusade but blue when he is revived in Legion.
- 补丁 2.0.12 (2007-04-03): Added.
Kazzak the Supreme
Legion field commander on Azeroth