MTL - My Fury Will Burn The Heavens - v19 Chapter 48 found it

[Tower Defense & Dungeon Attack RPG] I saw the ending to the game no one was able to clear.

But, when I came to my senses, I was inside of the game.

In fact, I was in the tutorial stage, a place where strategy was impossible.

“I’ll clear this bullsh*t game no matter what…!”

Humanity was on the brink of destruction. Muyoung, an assassin from the Forest of Death, fell to his knees. There were corpses all around him. For years, he had worked for the Forest of Death and had finally been able to eradicate them. Now, he, himself, was about to die. He closed his eyes as he felt his heart stop beating.

After the nuclear warfare, massacres started to spread throughout the entire world. The order between humans completely collapses, and the strong eats while the weak gets eaten becomes the #1 rule.

Easily cowed and bullied, she was the useless, ugly woman with no talent in medical skills. Supported by millions, he was Tianning’s most respected duke with the power to move all under Heaven. On their wedding day the bridal sedan was carried to the front doors, but the Duke of Qin’s gates were shut tight.

They told her, ‘Come back tomorrow.’

All alone, she walked step-by-step full of pride through the duke’s doors. Little could they imagine, this unattractive good-for-nothing was a beautiful, genius doctor of poisons!

—

After transmigrating to the past, poisons expert Han Yunxi finds herself on the verge of being married off to the country’s second most powerful man, the Duke of Qin. Her future life seems set–except her husband is an unfeeling ice block, her in-laws think she’s a eyesore, the empress dowager wants to use her for her own goals, and poison-related plots abound.

Alone, the intelligent (and sensible) Yunxi must carve her own space from the intricate web of court intrigue and the jianghu, relying on her words, wits, and wisdom to survive. Adapt when necessary, use force when required; to survive and thrive is the name of the game to a prosperous life.

No matter what, she’ll prove her right to live!

- Description from novelupdates