Lore:Zenith Lore Rambles
The Dyson sphere doesn't have a whole lot of secret backstory, but here are a few things that I guess may not have been said in the past: essentially this is one of the few remaining living Zenith entities.
Most of the actual Zenith died a couple of billion years ago, right? And so now we have these Golems that are basically desiccated ancients husks floating in space that we're quasi-reanimating and strapping electronics to in order to make them move and do things. We're basically puppeteering their bodies without their conscious mind remaining, when it comes to the golems.
The Dyson Sphere is different. It's still alive partly because its star is still living, but also because the huge calamity that befell the Zenith race bypassed it or wasn't able to conquer it or dislodge it from the star. Exactly what transpired there, I'm not sure.
But at any rate... contrary to popular belief in our galaxy, there ARE some Zenith still alive in the universe, but they're trapped in a zoo-like state on the planet seen in Stars Beyond Reach. Those Zenith are stunted and small (only a few hundred meters across, not kilometers like the space-based ones). Those other Zenith have been trapped for a very very long time by the mysterious thing that holds all the races found on that planet. The same thing that destroyed those races in the larger universe is what collected them onto that planet.
This befell all the Last Federation races, actually, who were from a different galaxy than ours and also several billion years in our past. The last Hydral, which is immortal so long as he doesn't get killed, shows up again even farther into the future when the last stars are dying out when it's time for Starward Rogue.
Anyhow, so there's this race-ending calamity that's tootling around the universe. It got some but not all of the spire, so they show up in SBR as well. Like the Zenith, they are stunted in size, there.
The Zenith themselves were a very ancient race before they died, and their initial origins weren't known even to them. They presumably started out as some form of planet-based life, but eventually transcended that and became space-faring entities that are basically part organic, part construction. We'd be tempted to call something like that a cyborg, but that implies that one section is literally machine and that another section is fully organic. That's not really the case with the Zenith... they're cohesive units simply built out of different materials, much as we have quasi-inorganic parts to us (bones, vaguely). They actively build themselves into the forms that they choose, using conscious control of their microscopic biome, rather than having that biome be emergently controlling them via DNA like we are.
The Zenith basically took control over their own evolution, and for the most part stopped reproducing and instead focused on what we would consider mutating individuals that already existed. They made these changes to themselves very very slowly, and based on the interests of the individual. They encountered a variety of hostile races back in their original time, so naturally they also developed a variety of weapons to fight with -- and those wound up being a part of their own bodies, rather than something separate. "Hooray, bob now has a gun nose." ;)
The dyson spheres are a bit special, because while all this was happening they took on one of the ultimate challenges, and received something closer to immortality from it. They grew so vast that they encased a star, which is multiple orders of magnitude larger than any other golem (most of which are on the kilometer scale). Even the devourer and nemesis -- okay, so those are actually two other survivors of the zenith race, come to think of it, along with the trader -- are tiny by comparison, being only roughly planet-sized. Not that super huge a planet, either; somewhere in the super-earth range, but nothing compared to a jovian. So actually, we know of a number of zenith survivors, but they're few enough that we can count them on our fingers, anyway.
Anyway, long story short, the zenith considered themselves to be beyond evolution, and they certainly were beyond natural selection for a super long time before most of them bit the dust. The dyson spheres are the largest organisms in the known universe so far, and I think they would consider themselves to be the pinnacle of the pinnacle. It's important to remember that even having a full-blown zenith golem buzzing around them is the equivalent of us having a single bacteria show up. We can't even tell its there, and if it bugs us then we send our immune system after it. We're not communicating with the dyson sphere because it's so large and so old that it's not clear what its perception of time even is. Is it hyper-intelligent? We don't know, at least not yet. Is it processing time on a different scale? Would we have to speak super slowly (by the standards of our metabolism) to have it even register what we were saying? Again, not clear. We haven't had time to study them yet, what with the war.
The devourer and nemesis, large as they are, are some of the few entities that the dyson sphere can probably even perceive. They are along the lines of gnats to us.
At any rate, what we think of as a dyson sphere being angry or having any other emotion really is likely no such thing. We're dealing with a subsystem of a subsystem, at best. If anything, what's showing up from the dyson spheres that are "aggravated" is a lot like an immune response in our bodies to a problem at a cellular level that we don't even notice. We may have pissed off some tiny tiny sub-component of the dyson sphere's larger network of... zenith biology... but it's probably not too aware of us. It's not even clear if those parts of its body are independently sentient or not -- probably not, which would explain why the dyson sphere is able to switch "emotions" so quickly and completely. We go from being seen as a foreign body, to a hostile foreign body, to a symbiotic microorganism, as far as it's concerned.