Tsutomu Nihei: Blame torrent

Killy is a man of few words. He wanders, seemingly endlessly, through a lonely, gargantuan labyrinth of concrete and steel, fighting off cyborgs and other futuristic nightmares, searching only for something called Net Terminal Genes. And he has a very powerful gun, which he uses without hesitation whenever anything resembling danger rears its ugly head.
Who is this quiet, violent, determined man and what are these Genes he seeks? The small communities he finds tucked into the crevices of this towering, dystopic ruin hardly give him leads on his treasure, driving him to find larger enclaves of civilization where people can reveal more about the world he lives in and the quarry he seeks.

Plus:
Blame Gakuen! And So On Manga

Collection of Blame-related short stories:

• Zeb-Noid
A bloody war that spans millenniums. Two soldiers set out to kill each other. An encounter that could change their two species’ fate forever.

• Blame Academy!

• Blame Academy! - Tokyo and Nara Under One Umbrella

• Blame Academy! - Under the Tower of Blooming Sakura

• Parcel

• Blame! NSE (NSE: Netsphere Engineer)
The much-awaited sequel to BLAME! follows a man, called a Dismantler, who is in charge of sub-dividing the nexus towers that incurr Safeguard interference upon its detection of humans without the net terminal genes. Although humans are once again able to reside in the Net sphere, the Safeguard are still a threat. The Dismantler or NSE, or Net sphere engineer, goes on a journey to aid mankind in their survival.

• Pump

• Blame!²
The protagonist is a descendant of Pcell. This story happens a long time after the events of Blame!. This young silicon creature knows well the havoc that Killy brought and decides to move towards the end of the megastructure, to look for him.

• Numa no Kami

• Winged Armor Suzumega
While it’s not explicitly mentioned in the story, it’s believed that Suzumega is at least somewhat related to Abara since it features the Gaunas.