Manaforge Duro is one of the five facilities that "collect" the mana energies from the air of Netherstorm for Kael'thas' blood elves. It is being used near full capacity, and mana creatures are leaking out of the pipes as a result. It seems that the blood elves did not create the buildings but only conquered them. Manaforge Duro is also the home of Summoner Kanthin, one of the most senior magisters of Prince Kael'thas.
Duro is located on the floating island directly west of Tempest Keep.