Spider Mastermind

The Spider Mastermind (also known as the Spidermind or Spiderdemon) was a leader of the forces of Hell. The Spider Mastermind is a Spiderdemon, appearing as an immense exposed brain, with two useless arms and relatively humanoid facial features. Incapable of movement on its own, it is grafted to a four-legged chassis that provides movement and possibly life support. The Spider Mastermind is armed with a "Super Chaingun" that launches explosive rounds. The Spider Mastermind, alongside the Cyberdemon, lead an invasion of Hell's forces to dominate the UAC facilities on the twin moons of Mars; Phobos and Deimos.

The Spider Mastermind resided in the city of Dis, and was killed by a lone UAC Marine. While more members of its species have been shown in action, it is possible that, after this event, the Icon of Sin and the next acting Dark Lord, the Maledict, decided to demote the Spiderdemons to a similar level of a Cyberdemon. While the original Spider Mastermind was killed in 2022, its soul remained active, and rose to the rank of Dark Lord by 2149. It met with a UAC scientist named Olivia Pierce, corrupting her into a demonic cultist and organizing an invasion plan with her. It offered to cure her illness, but truly intended to just use her as a means to be properly reborn. When the invasion began, the Doom Slayer, the same marine who originally killed the Spider Mastermind, was awoken to stop it. The Mastermind fused with Olivia Pierce to regain its physical form, but was finally destroyed by the Slayer after being cornered in Hell, its invasion force depleted. After its death, the Maykrs and Hell Priests took direct command of the invasion, with pieces of the Mastermind being used to create Arachnotron-like clones for the renewed invasion of Earth. Other Spiderdemons have also been referred to with the title of Spider Mastermind.