Female Warrior - Volume 2, Chapter 3: Number, 3, The Third One

A former sporting rifle shooter genius transforms into the ‘Juvenile Butcher’. While originally supposed to have received the death penalty, he was instead fortunate enough to have entered a secret and highly regarded armed force, throwing himself into the ‘Nirvana Project’.

Before his death, he was the only sword cultivator in the whole world, who dedicated his entire life to the path of sword immortality.

When he opened his eyes again, the world had completely changed. He began to cultivate the path of sword immortality again, slaying the heavenly way, shattering the universe with his will, and achieving the realm of sword immortality!

- Description from Novelupdates

Dual cultivation and apocalypse—words that mix like oil and water. There's nothing charming about seducing feral women on the road.

However, when Kaze Lexicon, the emperor of the Immortal Plane, got transmigrated into the past, he refused to give up his debaucherous ways—apocalypse or otherwise.

Armed with the knowledge of the future and an encyclopedia of overpowered cultivation techniques, he immediately set forth to obtain resources and build a lavish settlement to live a comfortable life dual cultivating in the apocalypse.

However, while it's obscenely protected and powerful, he finds himself in another predicament. The cultivators farming humans for their war, and the desperate humans, become enemies far more dangerous than the zombies and monsters that afflict humanity.

Join Kaze as he rebuilds his reputation from a bullied weeb, obtains wealth, builds power, starts a faction, makes lemonade, trains his people, protects his past lovers, conquers settlements, and fights humans, monsters, and cultivators, all for the sake of two obscene goals: enjoying life and building an army of engineers to bring modern technology to the higher planes.