A Nexos is a type of Genestealer Hybrid that is a consummate strategist. If the Clamavus is the Genestealer's Lorgar, than the Nexos is the Genestealer's Papa Smurf. By analyzing and interpreting every subtle ebb and flow of battle, they can identify vulnerable positions for their kin to exploit, pointing out potential flanking routes and subterranean passages perfect for arranging sudden ambushes.
Due to his role the Nexos shouldn't ever be in a position where he should have to shoot (or worse, be shot at), but seeing how precarious the life of a Genestealer Cultist really is, he is armed with an autopistol for self-defense.
While the Primus is a frontline battlefield commander, the Nexos is more akin to a rear echelon officer. Coordinating billions of indoctrinated souls on a planetary scale, Nexoses are unique bioforms created by a Patriarch to undertake the organizing and execution of full-scale uprisings.
These creatures are imbued with a fraction of the cerebral might of a Patriarch which allows them to act as the central nervous system of a Cult. These gifts give them strange, psychometric powers that allows them to absorb the memories and consciousnesses of indoctrinated organisms, processing the sensory data into a steady stream of strategic instructions and deployment orders. For lack of a better description, it is the Genestealer's equivalent of the Adeptus Astartes Omophagea, but somehow even MORE icky. By laying their hands upon the skin of a creature with Genestealer taint, a Nexos can absorb their genetic memory to the extent that they can see the subject's entire life.
Because of the Charles Xavier-esque mind powers, they can compartmentalize millions of these mental imprints inside their brains, building an incredibly complex three-dimensional view of the battlefield. However this process is draining for both the subject and initiator, for the human body is not meant to channel such potent neural processes. As a result, the Nexos is physically worn and strained.
In battle, a Nexos rarely emerges from the Cult's hidden lairs unless a first-hand view of the engagement is required, or it is necessary to absorb the memories of enemy troops. In the rare situations where they are directly confronted with the enemy, they call upon squads of Genestealer Hybrid and Aberrant bodyguards.
The support unit of support units, this guy is really useful for the Genestealer Cults. The Nexos as the strategic commander has some really cool abilities. Firstly, he allows you to redeploy one Ambush Marker so you can mess with your opponent even more. In addition, he’s got the Strategic Coordinator ability which can allow you to farm back Command Points when you or your opponent spend them, which can itself be enhanced by the presence of a Primus or Clamavus.
As previously mentioned in the fluff, he's only got a basic autopistol to defend himself since he's not meant to be on the front lines, so put him in a position that is out of reach from assault units, deepstrike units or artillery bombardments. Protect him at all costs.
- Here is a cool easter egg. The holo-map that the Nexos is reading on is the same layout as the buildings from Warhammer World. Pretty sneaky there Games Workshop.
- The communication device he is holding is very reminiscent of the Walkie Talkies used by US soldiers in the Vietnam War. Seeing as how Genestealer Cults like to fight like space Vietcongs, this might be a nod and a reference.