King of Something or other
Well you could do a man vs machine war or a low tech rebel faction against a high tech superpower. Either way, the low tech or human force creates the virus as a last ditch effort to destroy the other side. They can either be fanatical enough to accept the near destruction of civilization as a necessary consequence or severely underestimate how damaging the virus would turn out to be.
Maybe the robot laborers acheived self awareness, but the humans reacted by trying to issue a patch that mind wiped them. So some of the robots retiated by ensuring that their mindless corpses could still fight back.
Questions arise regarding how much scifi hardness you want.
You may want to consider the choice of a universe-destroying war versus a galaxy-destroying war and the scale involved and so on. Even a single galaxy is difficult to conceptualize the size of. A universe-spanning anything is gonna have some implications...
...unless you're working with a tone where the actual scale of space doesn't matter.
According to physics as we understand them in the real world as regards the energy involved in space travel, any civilization that can easily go a-spacefaring can easily exterminate all life on any given planet. That makes it kind of hard for any sort of war in space to be anything less than a catastrophic destroyer of civilizations.
Perhaps this robot wrecker virus was deployed because it was the least destructive way to disable everyone's fleets of automated, planet-popping weapon systems and give the few remaining points of life a hope of survival.
Show an affirming flame
Sounds like an analogue to two sides deploying biological weapons against each other, except presumably much quicker and more destructive—computer viruses on steroids. If cybernetics were sufficiently advanced enough for brain/computer interfaces, that could potentially mean mass biological casualties as well.
An analogy could be found in Charlie Stross's Glasshouse (it's almost become an axiom that whatever cool idea you had, Stross did it first) with the Curious Yellow virus. It was deployed in a long-ago war and nobody knows the details, because Curious Yellow had been programmed to erase that information wherever it found it.
As for why they'd be unleashed against each other, Mutually Assured Destruction—which something caused to break down, unleashing a "use it or lose it" logic down the command chains.
edited 6th Nov '16 7:26:11 PM by SabresEdge
Charlie Stross's cheerful, optimistic predictions for 2017, part one of three.
Okay, so the premise for my story is that (1000 years into the future) 500 years ago, there was a war in space that left the universe in ruin. A computer virus left most technology unusable and all life was forced to survive on scattered planets across the universe. That is until our merry band to protagonists find an unscathed spaceship, it's crew, and go on wacky adventures together!
I'm pretty happy with my characters. The problem I have right now is what started the war in the first place, and what would lead the conflicting nations to basically collapse all advanced civilizations and leave travelers stranded?
The main adversary my protagonists will be facing is a virus that basically turns robots into very shiny zombies (if said robots haven't shut down or exploded already). But who would be crazy enough to create a virus like that. I know I'm basically making Fallout 4 mixed with Star Wars, but I don't wan't to have 'The War' just be the Cold War or WW 2 in space. I mean, when one of your character's is a genetically modified ninja chicken that's married to a space ship, generic is not a word you want associated with your story.
IDK, maybe I'm looking at this wrong. Perhaps the war isn't necessary and it could have just been one relay crazy dude that said "Fuck it, let's kill everyone!". perhaps I'm pidgin-holing myself too much and WW 2 in space is a good idea. Perhaps I should have a different antagonist than 'zombie robots'.
I'm in a creative rut and research ain't helping. It's all pretty conceptual right now so all suggestions are welcome. Thank's for reading :D