The Nexus is a giant Necromorph encountered by Isaac Clarke and John Carver on Tau Volantis during the events of Dead Space 3. Similar to the Hive Mind that Isaac encountered on Aegis VII, the Nexus serves as a sort of "commander" for lesser Necromorphs, telepathically relaying the signals of the Markers and thus coordinating the infestation. Several Nexus forms are encountered on Tau Volantis, most of which are frozen solid, but one specimen is intentionally revived by Isaac himself who activates the creature's interior nerve clusters so that he can use the beast to track down the alien device that keeps the planet frozen. Though the Nexus does take Isaac to where he needs to go, it then attacks him afterwards.
The Nexus is a very large crustacean/insect-like Necromorph. It possesses four known limbs which it uses to attack with. The head is very mantis-like and has four eyes separated by a large fleshy opening down its crowned forehead. Its vertically split mandibles when open reveal two large claws and five large pustules which surround its mouth. The chest cavity opens to reveal a large glowing pulsating sac similar to the Hive Mind. During combat it uses four of its long limbs to attack while two blade like arms rest behind the head. Also shown inside the body after Isaac is swallowed, he is attacked by three Nests.