Sargerite Keystone

The Sargerite Keystone (also referred to as Sargeras' keystone) is a fel-corrupted titan device, created by Sargeras himself, which serves as a skeleton key allowing travel to any world. Sargeras originally created it to lock away the demons he'd imprisoned in Mardum. When he shattered the realm and formed the Burning Legion, he safeguarded it on one of Mardum's fragments by entrusting it to Brood Queen Tyranna.

During the war in Outland, the Illidari demon hunters were sent by Illidan Stormrage to retrieve the keystone for their master, after he ran out of time to enact his original plan of opening a portal to Argus with the Seal of Argus. The Illidari were successful in retrieving it after killing Tyranna, and they used the keystone itself to return from Mardum to Outland. However, they were subsequently captured by the wardens led by Maiev Shadowsong as they returned from their mission. The Sargerite Keystone, now in possession of the Wardens, was then held in the Vault of the Betrayer, where Illidan's body was kept.

Years later, during the third invasion of the Burning Legion, the wardens freed the Illidari and the two groups worked together to retrieve the keystone from the felsworn Cordana Felsong who had stolen it for the Burning Legion. It was brought to the Fel Hammer, the order hall of the Illidari.

Some time later, when the Armies of Legionfall invaded the Tomb of Sargeras, the Legion ship used by Kil'jaeden began to crash toward Argus after the demon lord was killed. Illidan used the Sargerite Keystone to open a rift between Argus and Azeroth, allowing Archmage Khadgar to teleport everyone safely back to the surface, in Azsuna. The immense rift that was opened between the two planets allowed Argus to become visible in the skies of Azeroth.

• This item is dropped by Brood Queen Tyranna in The Fel Hammer on Mardum for the quest The Keystone (quest).
• It is also dropped from Cordana Felsong in the Vault of the Wardens for the quest Vault of the Wardens: Vault Break-In and is used in follow-up quest The Crux of the Plan.