To be fair, we don’t really know what the Darkness is yet. Oryx did take from the Deep, yes, but he took the Tablets of Ruin, not the Darkness itself. From verse 3:8:
Auryx the First Navigator set upon his god with his sword and his words, and cut Akka to pieces, and took from those pieces the secret of calling upon the Deep. He wrote this secret on a set of tablets, which he called the Tablets of Ruin.
He found a way to call upon the Darkness, that is, Take. He also spoke to the Deep, but we don’t know what that speech included. As for what form the Darkness itself takes, there have been a variety of theories since D1, but we won’t be sure until we get more information.