MTL - The Melon-eating Swordsman In the Ancient Dragon World - Chapter 355 Lu Xiaofeng: This is a very simple reasoning

Tóng Yáo woke up and found herself in an unfortunate situation.

Not only did she transmigrate into a fantasy-romance novel that had been dropped by the author, she transmigrated into cannon fodder that was fighting against the protagonist for a man!

In order to keep living, Tóng Yáo immediately reached forward to grab the protagonist’s thigh.

“Mistress, I was wrong!”

- Description from Novelupdates

An editor at the prime of her life—and with maybe just a little too much free time—finds herself waking up in one of her favorite RPGs with no clue as to what's going on or how to get back home.This might be the part where others rejoice over getting whisked away to a world of wizards and magic, but she certainly doesn't think it's anything to celebrate about.After all, she woke up in the body of a small-time villain with some severe personality issues.

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

Lin Wudao transmigrated and obtained an invincible system to bury corpses.

So long as he buried the corpses of the powerful, he got to take over what they had or what they touched as his bonus. What was more, those items he stood to win were the enhanced versions.

The minimum level was enhanced by ten times!

“You’ve buried the corpse of Jiang Taichu the Great Emperor. Your cultivation prowess just increased by 10,000 years!”

“You’ve buried the corpse of your fiancee, Jiang Qingxue. You get the essence of the immortal, which is enhanced by 100,000 times! It’s thus upgraded into the essence of harmony. You will become the Immortal Emperor after the extraction of it!”

……

Ever since he acquired this system, Lin Wudao had embarked on an invincible journey of advancing history and dominating the world.