Apparatus
The Apparatus was a magical machine first manufactured by the Alchemist Strahd. The massive device, a conglomeration of crystal, metal, and glass spheres, has since been reconstructed in many realms, as the plans for its construction have mysteriously found their way into many hands. The Apparatus is normally capable of transferring the souls of two beings into one another's bodies. However, with the addition of the Rod of Rastinon, the Apparatus can do even greater things. It may split a being in two, dividing them into two diametrically opposed beings (good and evil, wise and foolish, etc.), or combine two beings into one amalgamated whole. Another object, the Rod of Houtras, simply activates the soul-exchanging power. The Apparatus has been used several times, most notably by the Alchemist and Creature Strahds, and the High Master Illithid of Bluetspur.
