MTL - Great Xuanwu Sheng - Chapter 81 massacre

Although Leng Ruoxue is born mentally challenged, she is the most beloved granddaughter of the number one general in the Eastern Lake Nation. She is despised by her fiancé and schemed against by her love rival. However, she is reborn as a powerful soul. This is a fantasy world, and also a world where the strong are respected. Cultivation, alchemy, weapon refinement, beast taming—the once foolish young miss has transformed into a stunning genius. Pill refinement and weapon refinement are all child's play. Heaven Grade medicinal pill? Even my pets won't turn an eye to it. Heavenly Treasure? I have the space to grow my own. Sacred artifact? Sorry, that's too low a level. I only know how to refine divine artifacts. Beast taming? My beasts deliver themselves to my doorstep.

The Universe is collapsing, and the realms are merging. To ensure humanity's survival, the heavens blessed the race with [talents] but that is far from enough. Only the gatekeeper can return the balance and stop the collapse, but why does it have to me?If the heavens think they can dictate my fate, I will make them pay the ultimate price...This soul will not be controlled...This soul will not be manipulated...I will cover the heavens with one hand!

The scum’s or villain’s long road of transformation was tentatively set to the world:
The abandonment of the educated youth’s wife (Completed)
The hidden marriage of the scum film emperor (Completed)
The best brother in the world (Completed)
The Phoenix male who destroy the bridge after crossing the river (Completed)
The treasonous general (Completed)
I’m an honest man (Completed)
To become the top scorer in the School of Agriculture (Completed)
The soft rice man’s self-cultivation (Completed)
The whole world is reborn (Completed)
I want to survive on a desert island (Completed)
The stallion male who has seized the opportunity (Completed)
The perverted self-salvation (Completed)
The spring of the loafer (Completed)
The misplaced life (Completed)
The miser career (Completed)
The ghost is out of feeling (Completed)
The Queen’s favorite husband (Completed)
The vicious girl with her godfather (Completed)
I want to be a good person (Completed)
I does not tear up the family (Completed)
The perverted common plant (Completed)
The Mary Sue’s men (Completed)
Every time I was reborn, someone wants to kill me (Completed)
The old people’s counterattack path (Completed)
The global evolution (Completed)
When I became a net red (Completed)
For you, good person (Completed)
His heart had white moonlight (Completed)

- Description from Novelupdates

A weary historian dies and finds himself in a different world awakened in a life as the notorious young Duke of a southern state. His nation is weakened, his army underfed, and his neighbors revolve around his lands menacingly. No one believes his land is going to hold out until winter.But this newfound duke is no naive simpleton his enemies recollect. He carries with him the experience of centuries of war and empire, of starting and ending monarchies. From Caesar to Napoleon, from the Mongols to world wars, he has learned from each of them—and his strategy is to make history his very own arms.He organizes his smashed levies into well-trained formations, rebuilds his castles, and turns his villages into supply centers. Where others see defeat, he senses opportunity. As he triumphs, rumors spread: of a pennant red as winter snow that shall not go to ground, of a bloody duke who writes his name in gore and flame.Is he a savior who's constructing a new empire, or a tyrant who's going to bring the world to endless war?