I always thought the Nexuses were simply buildings (constructions) to help Aridon channel his power to control the undead.The fact that each Nexus is a different self makes it alot interesting. This can also mean a weakness in the undead army as it kinda made clearly that not all the Nexuses envision world the same as Aridon, wich means that even the undead army can be divided somehow.
What I don't exactly understand is that, the undead that belong to a Nexus share the same mind with the Nexus , or each undead has free will ?
When Aridon leaves:
The Zirr Nexus: I see them as preservers of history and knowledge , I think they will remain neutral in the world and simply watch and learn.
The Splecir Nexus: There zealotism might blind there actions and force the ''Will of the Master'' on a very different way.
The Ardoz Nexus: Mad scientist undead , probably will experiment more and more ways of torture to satisfy there lust of agony.
The Rohir Nexus: For this I have one question, they can take mortal form , ( the Emisary that brought news to Marin about the GG being traitors ?

)
The Scarec Nexus: It's my personal favourite

, and I think the most dangerous out off all the nexuses , for it is clearly stated that the only thing preventing them from mass genocide ( also undead included) is Aridon.
The Kezzar Nexus: I think they might take some action against the Demons Realm if Ornasion simply lets revenge overcome his judgement.
The Lenira Nexus: Probably I close path such as the Splecir Nexus.
The Ejara Nexus: Can't say anything about them , they will keep and hatching
