One-click Training System Instantly Millions - Chapter 5: System functions can be upgraded!

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

Kim Taejune, wanted to be a “hero,” a “savior” to all the weak. After reading books about them, he too wanted to be one. Yet he lacked power, he didn't have any skills, and the command system everyone else had but one day, his dream will come true. His path leads him to encounter Yoon Harin a woman who after the death of her twin younger brother Yoon Jiho was transmigrated into his novel, “Calamity Hunter” the “god” of this world makes a deal with Yoon Harin to bring her brother back to life IF she can survive as a savior till the end.

Despite being the ruler of a nation, nobody was willing to marry the vicious man with a bloodlust.

Jiang Liu lost his father at the age of three. When he turned five, his mother decided to run away with another man. At the age of fourteen, he sent off the only relative he had, his grandfather, before carrying a small amount of property and stepping into the big dyeing tank called society.
He was stingy, selfish and absolutely disgraceful. Except for breaking the law, he accumulated all the bad habits available to the mankind. Yet, such a man, after an unexpected death, was bounded by a silicon-based creature called the righteous father’s system. Since then he started his magnificent career in the world system.

World 1: On the ultimate evolution of unquestioning filial piety;

World 2: The man who loves to boast;

World 3: The search for the second spring for ones own mother

World 4: Good father

World 5: The self-cultivation of a national husband

World 6: Acrobat

World 7: Divine stick

World 8: My home has a baby egg

World 9: The correct way of wearing the green hat

World 10: Tremble, you scum man

World 11: An angel who doesn’t like to talk

World 12: The rebellion plan of a martyr

After several worlds went by…..

Righteous father’s system 001: [Shivering], I wonder if I still have time to change my host.

- Description from Novelupdates