Spiderdemon

Spiderdemons are highly intelligent non-humanoid demonic commanders.

Biology
Spiderdemons are large, usually sessile beings, resembling brains. They bear grey semi-humanoid faces with red eyes and sharp teeth. They appear to have either no nose or a very small and indistinct nose, and their features appear notably sunken, angular, wrinkled, and almost skeletal, but any internal skeletal structure is unknown, as they appear to be almost entirely brain, similarly to Kalibas' species. Their essence is able to fuse with Humans, which can allow them to grow four partially organic crab-like legs, makes them far larger, and makes their features oddly appear more alien, with two split jaw components bearing extra teeth. The only visible organic limbs on an unmerged Spiderdemon are two spindly, near-useless arms present near their faces. Notably, their souls can survive long after death, which is what allows them to merge with Humans and regain an organic body. Their usual cybernetic chassis consists of a blocky "seat" with four mechanical legs, and an oversized chaingun on its underside. Spiderdemons are known to be very durable and highly intelligent, even able to psychically control other demons, even powerful demons such as Baalgars, but this may have been exclusive to the Spider Mastermind, which became the Dark Lord. The Spider Mastermind also bore a unique cybernetic chassis, which seemed to somewhat resemble the cybernetic exoskeleton worn by Dr. Olivia Pierce, and carried a powerful energy cannon on its underside. While Spiderdemons have been described as both male and female, there appears to be no visible distinctions between genders. Young Spiderdemons, often referred to as Arachnotrons, have light grey bodies and blue eyes, mostly resembling a far smaller version of the adult Spiderdemons, and are given similar cybernetic mechs with plasma cannons. Cloned Spiderdemon genetic material can create Arachnotron-like beings.

History
Spiderdemons came from a demonic dimension known as Hell. They rose to commanding ranks in the invasion of the multiverse, like Tyrants and Arch-viles, and at some point in time, the demons either built or stole cybernetic technology that allowed the Spiderdemons to be grafted to a quadruped chassis. Their cybernetics allowed them both mobility and combat power, with one Spiderdemon, taking on the title of the Aranea Imperatix, rising especially high in the ranks. By the fourth age, the Aranea Imperatix became the Dark Lord, now known as the Spider Mastermind. In 2022, the Spider Mastermind, seeing that Union Aerospace Corporation scientists on Mars were testing teleportation technology that used Hell as a slingshot, organized an invasion force to conquer their universe, appointing a Cyberdemon as its commander. They pulled Deimos into Hell, with the Cyberdemon being put in control of the moon, while Phobos was assaulted by demons, being put under control of two Barons of Hell. A squad of Human US marines assigned to a UAC Martian base as security were sent to Phobos to retake it, but were almost completely slaughtered by the demons, leaving only a lone, unnamed marine. The marine fought his way through the base, singlehandedly capturing Phobos, taking the teleporter to Deimos, killing the Cyberdemon, and fought his way to the Spider Mastermind, who resided in the Hell city of Dis. The Spider Mastermind fought him, and was destroyed by the marine, allowing the marine to return to Earth. However, before it was killed, the Spider Mastermind had sent demons to invade Earth, assaulting the city that the marine arrived at and killing his pet rabbit, with command of the invasion being taken over by the Titan known as the Icon of Sin. As the marine fought his way through the invading hordes to the Icon of Sin, he killed more Spiderdemons who stood in his way, including young Arachnotrons. All surviving Spiderdemons were sealed away in Hell when the Icon of Sin was killed.