Moto Sekai Ichi'i no Sub-chara Ikusei Nikki - Chapter 66: Royal Court Magicians

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

The Mc reincarnates in a world of magic and adventure as a Leech, follow his adventure in this mysterious and exciting world as he goes from the weakest creature to the shadow being that everyone is afraid of. Will he pursue the path of strength alone? Or without realizing it he will become the king of the greatest empire that ever lived.

A cauldron, a secret forging method, and his blood created an ultimate weapon. The youngest Sword Crafting Master on Earth had been reborn from another world. With the Nine Yang Divine Furnace and a scroll of Divine Equipment, he was like a fish in water, standing at the pinnacle of the martial way. There were tens of thousands of clans, billions of cities, and countless experts. He was the master of ups and downs!

Li Xu occasionally got a sign-in system, and his life has been different from now on. Enjoy life, look at the scenery, sign in, spring flowers bloom, and face the sea.

- Description from novelbuddy