The Soul Cannon of Reth'hedron

Reth'hedron now lords over the Twilight Ridge of Nagrand. An eredar of such power being loosed upon this world does not bode well for the Illidari. Alas, we do not have the resources required to slay Reth'hedron. Not with the war the Sha'tar have brought to the Black Temple. No... I have a better plan. You will subdue Reth'hedron, banishing him back through the Twilight Portal. For this a soul cannon must be fashioned. Return to me with the materials on this list.