The Nexus is a massive Necromorph encountered on Tau Volantis. Much like the Hive Mind encountered on Aegis VII, the Nexus serve as ground commanders for lesser Necromorphs, telepathically broadcasting Marker signals and coordinating infestations.
Several Nexuses are encountered by Isaac during the events of Dead Space 3; all are initially found frozen solid, although one later thaws and revives. In order to continue progress in the mission in destroying the Markers, Isaac has to activate the nerve clusters inside the Nexus' body cavities, which are used to create a signal to track down the alien machine. Soon after, due to being thawed and irritated by the probe gun, the specimen escapes (much like the one from the warehouse with the probe gun parts did), and acts as a boss for the chapter.
The Nexus is a gargantuan crustacean-like Necromorph, and only its upper body section is shown during the fight. It appears to be created from at least one corpse belonging to the extinct alien species native to Tau Volantis; its "head" resembles the skulls of the alien skeletons seen later in the game.
The Nexus can shoot many red pustule projectiles that explode upon contact and swing its massive claw-like appendages down on the player. When the pustules aren't disturbed, Feeders can burst from them and attack. The player must first target a large sac on its stomach, then destroy two of the yellow pustules on its mouth while the Nexus attempts to swallow the player. This must be repeated twice before the second fight sequence.
After shooting all of the yellow sacks, the Nexus attempts to swallows Isaac and/or Carver a third time and are slowly pulled into its stomach. They are plunged into an organ filled with an acid substance. After being attacked by three Nests, the Nexus spits them out. After several seconds of a frenzy, the Nexus collapses, dead.
The Nexus is a very large crustacean/insectoid-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 Nest.
The Nexus has a hollow internal chamber which is covered in Corruption strands. Cyst like objects are located in corners. If shot at, they will summon enhanced Feeders to defend the stomach.
- If Isaac or Carver fails to shoot the yellow spots on its mandibles while it is sucking them in, it will suck them in and chew them up before spitting them back out. They will die if their health was low.
- It is best to use rapid fire weapons for targeting the the chest cavity's sac.
- As it pulls Isaac or Carver in, fire at the mouth's pustules. The pustules turn red as more damage is inflicted.
- Also use rapid fire weapons for the nests.
- Be sure to have a close quarters combat weapon (like a hydraulic hammer) when inside the Nexus. Flee to the cage when the fighting gets too rough after targeting the nerves.
- If you are using a rapid fire weapon, it is usually advisable to ignore the pustules that the beast spits out, and concentrate on the chest cavity. Once you deal sufficient damage, the creature will attempt to suck Isaac or Carver into its mouth, and all spawned Feeders will be consumed in the process.
- The Nexus possesses eyes and has a digestive system, strange considering that most Necromorphs are only composed of dead tissues and have no need for organs.
- The Nests in its digestive tract may be a secondary line of defense to kill anyone that the Nexus has eaten but not killed yet.
- Another possible theory is that since Tau Volantis was once an entirely aquatic planet, this life form is in fact a Necromorph version of a large sea creature.
- When the Nexus is killed, the player receives an achievement/trophy (if playing on the PS3 or Xbox 360) which states that the Nexus is a Hive Mind.
- In Chapter 11, several enormous creatures can be seen frozen in the ice shortly before the appearance of The Nexus. They all bear extremely close resemblances to The Nexus, hinting that there was or still are more than one on Tau Volantis.
- The design of its head strongly suggests the Nexus may in fact be a Necromorph variant of the ancient Alien species that existed on Tau Volantis before the arrival of humans. It may be a variant of the Hive Mind which was created from Alien biomatter as opposed to human biomatter, which was the main component of the Hive Mind on Aegis VII.