Speak to Menara Voidrender in the Barrens.
Well, well, well... a pleasure to see you're growing in power, [player]. I'd wager you'd be about ready to speak to Menara Voidrender in the Barrens. If you haven't spoken to her before, then let me tell you, I don't think I've ever met another expert in the creation of items--orbs specifically--that can inprison even a demon to serve our will so easily.
If you're interested, she's in Strahad's tower above Ratchet in the Barrens.