MTL - Reincarnated in the Alternate World, I’m A Demonic Lord as Well as a Villager - Chapter 60 The Power of the Envoy's Contract (seeking further reading)

Once an imperial princess, now reborn among the lowest of s*aves of the nobility.

[The 3000th Descent of Mystery is about to begin.][This is your only chance to redeem yourself.]When the whole world was in danger, Wang Teng activated a unique talent.It was the Rank SSS talent - Inequivalent Exchange!He was not purchasing things for free, but the exchange was not equivalent.[Exchange successfully. You used half a bowl of cup noodles. With your Rank SSS talent, you may retrieve an unlimited supply of cup noodles.][Exchange successfully. You used a bottle of Sad Breeze wine to exchange for the Star Shifting Method.]…From then on, Wang Teng activated a new exchange system.

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

My whole life, all I wanted was power.

I churned the world into rivers of blood and eventually gained the title, “Demon Lord of Strength”. However, all this became useless when I lost to a party of heroes.

But what can a loser say? As I laid dying, I was forced to listen to the hero’s gibberish:

“If you are born again, I hope that you will live a kind life!”

But huh? When I opened my eyes again, I was back in the past.

“What do I have to do to live a kind life?”

This is the beginning of an ex-Demon Lord’s journey to live a kind