Engibrains were the humanoid robotic servants of the Monstrons. Kenex and Yeq used an army of Engibrains in their attempt to conquer Skaro. Although the robots succeeded in entombing the Dalek City, they were destroyed by the Dalek that the Monstrons had captured when it sacrificed itself by setting off a volcanic eruption. (COMIC: The Menace of the Monstrons)
The psychoplasmic Golden City Zone within the Dalek Dome had a model of both a Monstron and an Engibrain in the Corridor of Conquests. (COMIC: Liberation of the Daleks)