BLAME! in a nutshel.
The megastructure goes on forever. It is constantly being rebuilt by the builders. The only way to stop this is with net terminal genes, Which nobody has.
Silicon life are evil cyborgs, they are the reason nobody has any Terminal net genes. They kill anyone with the net genes cause they want the megastructure to continue to expand chaotically forever.
Safeguard are robots programed to protect people with terminal net genes and kill anyone who does not have them. Unfortunitly because nobody has net genes they just kill everybody. They will fuck you up.
The authority created the megastructure and safeguard. However they are unable to control them with out Net Genes so all they can do is sit back and watch as everything goes horribly wrong.
Killy is a badass synthetic humanoid on a mission to find the Net genes and save the world. He is Gar to the max, He can survive being thrown through concrete pillars, Doesn't need to eat sleep or drink, and packs a tiny gun that makes big explosions. He's a pretty cool guy eh? Finds net genes and doesn't afraid of anything?
Killy is GAR, Things explode.