The Apocalypse Device was a creation of the Deathsmiths of Goth and was a powerful and deadly weapon.
It was in essence the ultimate weapon. It was a synthetic creature which carried every conceivable disease or virus, as well as the ability to broadcast telepathic nightmares that had the capacity to paralyse victims with fear. However, once it was created, the Deathsmiths' creation turned against them, forcing the Deathsmiths to destroy all their spaceships to prevent it from escaping Goth and wiping them out.
Its appearance was that of a wraith-like, ghoulish humanoid. It was an intelligent being but its sole purpose was to kill. The Apocalypse Device revelled in its acts and enjoyed killing anything that got in its way. However, it preferred a challenge and typically hunted its enemies one by one while gloating about the doom its prey would face.
Cyber-Leader Maxel of the Cybermen came to the planet Goth to gather some of the dangerous technology of the Deathsmiths. There it was stalked by the Apocalypse Device, which killed its men one by one. Maxel destroyed his ship and himself, leaving the Device trapped on the planet. However, a Sontaran craft arrived shortly after. (DWM: Black Legacy)