Lexington wrote:
Of course the C'Tan were motivated by scarcity, death and internal politics. That's their
whole story. They fed on a finite resource (suns), found an even more finite resource (alive things) that they liked better, then fell into war between each other over an even
more finite resource (themselves), killed each other off almost entirely, then went to sleep because their resources were threatened. Now they're back, looking to re-establish their dominance over the living to create a galaxy-wide farm of living things to fuel themselves.
The new Necrons don't really have any of that. They don't need resources to live, they don't have a finite lifespan, and hierarchy is baked into their bodies. Aside from kicking interlopers off of their lawns, they don't really need war, because they don't have the basic biological drives that necessitate expansion. There's the Silent King and his anti-Tyranid campaign, but that doesn't really make sense in the first place (grueling wars of attrition don't tend to leave you in a great position to face new threats). Heck, even if it did, doesn't that just make the Necrons the slave-minded zombie army all united into one purpose that people now say the 3rd Ed Necrons were?
Prior to their dealings with the Necrontyr they had no threats and seemed entirely isolationist with both each other and other species'. The method of feeding on stars the C'tan initially used was never mentioned to have dramatically decreased the lifespan of said stars. Considering the number of stars as well they were an nigh-on infinite resource. They then decided to go for tastier treats after the Necrontyr contacted them and suddenly stars became boring to eat. The C'tan basically became addicted to eating stuff. Their entire motivation was built around eating stuff. I want living beings. I want other C'tan. There aren't enough living beings. I have become incredibly impatient so it's time to go into stasis whereas before I'd feed from a star for millennia quite happily.
But yeah, before the Necrontyr contacted the C'tan the C'tan had no problems with scarcity, death or internal politics.
As for the new Necrons, they do technically have a lifespan (being imperfectly maintained\repaired\whatever). Half of the ones who remain sapient have gone insane to some degree or another. The Silent King wants to return his people to living bodies and reclaim their 'souls'. He wants to save the galaxy from the Tyranids so that Necrons can find new bodies with which to bio-transfer into. The Silent King himself is wracked by guilt by what he has done to his own people. He all but exterminated his own species and now there are only a relative handful that remotely resemble being alive and even those will continue to deteriorate until the Necrons eventually become extinct. He condemned them to a slow doom and only by defeating the Tyranids and reclaiming living bodies can they avert it. As for the rest of the sapient Necrons, they're driven by the last commands they were given by the Silent King. If I recall correctly those orders were to reunite the Necron empire and find a way to bio-transfer themselves back into mortal flesh.