Nexus

The Nexus, also known as a Nexus Organism or Hive Mind, was a massive Necromorph that served as a ground commander for lesser forms, receiving the control signal from the Markers and the Brethren Moons and relaying it to the smaller creatures around it. One such giant, raised from the long-dead natives of Tau Volantis, was thawed and fought by Isaac Clarke during his search for the Alien Machine. The smaller Ubermorph seen on Titan Station was understood to be an early stage of the same strain.

The Hive Mind strain#

The Nexus was the commander form of the Necromorph strain. Each one carried nerve clusters whose synapses could emit and receive bioelectric signals, and through this neural network it acted as a second-in-command during an outbreak, answering to the Marker and relaying its directives to the smaller creatures. The appearance of any given Nexus varied with the biomass it was built from, so that one could differ greatly from its hosts or resemble them closely. Whatever the differences, every Nexus bore a set of massive, antenna-like appendages on its back, thought to broadcast the Marker signal to other beings and to forward commands to the lesser Necromorphs. Common to all of them were a prominent rib cage and several weak points formed from sacks of yellow liquid.

The first known Hive Mind grew from human hosts on Aegis VII. It resembled a worm-like creature with a round mouth ringed by long, flytrap-like teeth, a rounded head set with yellow-sacked eyes, and a rib cage filled with the same fluid sacks. Marker 3A held its connection to that Hive Mind through a signal-amplifying pedestal; when the Marker was removed, the connection was severed and it could no longer relay orders to the creature. The much smaller Ubermorph, seen during the Titan Station outbreak, was understood to be the same strain at an early stage, since it carried the round five-eyed mouth, the prominent rib cage and the back appendages of a Hive Mind and was seen leading the Necromorphs toward the Site 12 Marker. At the far end of the strain stood the Brethren Moons, which shared the Hive Mind's pentagonal five-eyed mouth, worm-like body and back antennae, marking them as the end-stage reached through Convergence.

The Tau Volantis Nexus#

The Nexus raised on Tau Volantis differed sharply from the Aegis VII Hive Mind. It was grown from the planet's extinct native species, and its head resembled the alien skulls found later across the world. It was insect-like and gargantuan, with four mantis-like limbs used for travel, vertically split mandibles that opened to reveal claws and five large pustules ringing the mouth, and a head set with four eyes. A chest cavity opened onto a large glowing sac like the one in the Aegis VII Hive Mind, and several appendages rose from its back. Inside it carried a heart-like sac, a digestive system, a stomach holding three nests, and a belly chamber of nerve clusters that received Marker signals. Hollow internal chambers were covered in Corruption strands and lined with cyst-like nerve clusters that helped broadcast the signal and, when disturbed, summoned Enhanced Feeders that had been feeding on the creature's insides to defend it.

By the time humanity reached Tau Volantis, every Nexus on the planet lay inactive and frozen. The research team of the Sovereign Colonies Armed Forces named one specimen Nexus-001, the number marking it as one of several; three more stood frozen at the base of the mountain that hid the Alien Machine, caught in postures that suggested they had been climbing toward it or trying to tear it down to stop it from activating. The native survivors activated the Machine first, freezing everything in place, the three Nexus among them. To find the Machine, Isaac Clarke had to activate the nerve clusters inside a frozen Nexus and read the signals it received, which roused the creature. It attacked Isaac, Carver, Norton and the Unitologists who had ambushed the crew. Isaac and Carver fought it through its own body, targeting the sac in its chest cavity and the pustules around its mouth as it tried to swallow them, and were finally drawn down into its acid-filled stomach before the creature spat them out and, after a final frenzy, collapsed dead.