Data Apocalypse: Modern Firearms on the Path of the Assassin

A data-stream apocalypse in a wasteland world. Zombies, mutated creatures, and monsters from other worlds, including demons and magical beasts, all coexist here. A data disaster kept firearms from ever being developed. The assassin uses knowledge gained as a military enthusiast in his previous life, along with game-crafting skills brought by transmigration, to build and assemble firearms. He advances cautiously through this brutal world and shows no mercy.