A Reincarnated Mage's Tower Dungeon Management - Volume 6, Chapter 7 – Princess Adele Appears!

This is a story about the protagonist getting the system, going crazy in the biochemical apocalypse, producing aircraft and tanks, destroying zombies, saving good people and killing bad people.

- Description from novelbuddy

After being reborn in the ancient times before the Great God-Conferment War, Li Changshou becomes a minor cultivator. He is neither destined for great things nor great woe. His only dream is to live a long life as a cultivator. In order to survive in the cruel Primordial Times, Li Changshou tries hard not to accumulate any karma—killing inevitably leads to feuds.

Thus, he always plans thoroughly before doing anything and never allows himself to walk into dangerous situations. He hides his trump cards well, trains himself in escape techniques, refines poisonous pills, and masters his mystical abilities. Before making any moves, he takes on an extremely steady demeanor. Yet, every move of his ends up earth-shattering. Once he is done, he will disappear without a trace.

Li Changshou originally plans to remain hidden and safe in the mountain. There, he is supposed to cultivate until he ascends to immortality. However, everything changed one year when his master seems to think that their lives are too peaceful… He takes in a junior sister…

‘The moment I faced its enormous eye, an unbearable headache struck me. Just by facing it, the amount of information exceeded what my brain could handle.’

Excerpt from ‘Things I Encountered in Space’ by Terra race space adventurer ‘Con Arche’.

…No, I was just looking out of curiosity…?