Track down a powerful Taken Minotaur. Destroy it, then shatter the simulation core it leaves behind.
"...saw Darkness. But not in the abstract, not like the Speaker talks about it. Real, flesh and blood Darkness standing before me. It wore a Fallen Captain like he was a suit of clothes. It laughed at me. Reached out a hand. And then I was gone, off to somewhen else." —File 48743 from Praedyth's Ghost