On the eve of the End War, Highlord Ma'lash used the catalyst to contact Amon, who instructed Ma'lash to ready his people for war. Shortly afterwards, Dark Prelate Zeratul destroyed the catalyst in hopes of disrupting the Tal'darim's link with Amon. The device's destruction released a massive amount of void energy, and Zeratul experienced a vision in which he heard Tassadar's voice urging him to find the Keystone. Amon then began dispatching void entities through the catalyst's wreckage, while simultaneously collapsing the temple itself, in an attempt to kill Zeratul. Praetor Talis and her templar sacrificed themselves to buy Zeratul time to escape.