...he lost his etherium arm when Jace amputated it with his manablade, a blade stolen from the artificer in the first place, in order to access the absorbed mana stored in the arm. Nicol Bolas reveals that pitting Jace against Tezzeret had been Liliana Vess' plan all along, and Bolas had agreed in order to regain control of the Consortium that Tezzeret had stolen control of twelve years before. Bolas kept Tezzeret, or at least his mangled and mindless body in his keep in the Meditation Plane.

Tezzeret learned soon enough why Bolas had kept his body. After an extended period of time, Tezzeret's mind and body were finally restored, albeit with a few alterations by the elder dragon.