The Celestial Forges are Titanian structures built around Ultra Stars which draw their energy for power. The main purpose of the Celestial Forges is to create Titanian Armaments, such as Titanian Gauntlets. It is within the Celestial Forges that Uux is refined and made usable. The Celestial Forges are massive superstructures, large enough to fully encircle the Ultra Star and not take any damage from their close proximity.
A Celestial Forge around an Ultrastar, with a Planetoid nearby