Legend of Great Tang’s Twin Dragons - Vol 1 Chapter 9: Another Long Journey

He Lang died by his own hands for the sake of his imperial younger brother’s ambition, whom he loved. He was offered to be reborn in exchange for giving up his past romantic feelings. Reborn without the burden of his romantic feelings, he brings with him a manual to new worlds. He wholeheartedly followed the instructions of the manual to complete the tasks, not knowing that the originally slag gong was blackening…
He pleaded to his affectionate Emperor brother to release him, he pleaded to the paranoid prisoner next door, but until the end he remained baffled.
In the end, he discovered that the full name of the manual was – “Slag Shou Cultivating Manual”
Σ (っ ° ° °;) っ!

- Description from Novelupdates

Xia Xiaoluo never expected that a takeout delivery would change her life forever.

System, “You have a sickness. Moreover, you’ll have one in every world.”

Hao Ritian, “…”

System, “What’s wrong? Is there a problem?”

Hao Ritian smiled, “No, there’s no problem. I was just a bit excited.”

System, “…”

That smile intensified the system’s feeling of ominous foreboding. It has had this premonition since it learned the name of its host. Now it only prays that this is all its imagination!

Ps: Protagonist shou 1v1, the gong is always the same person.

- Description from Novelupdates

Layland Kleinhaus (17) suffers from hypogonadism that makes him less “manly” on top of having a girly face. He is bullied because of it, but he always remains strong ... At least, until he can't bear the betrayals and sufferings anymore.

Filled with rage, indignation, and the lust for blood, he decided to end the life of his tormentors along with the bystanders before taking his own life.

Alas, in the middle of his deed, a mysterious being intervenes the act by summoning him and the rest of the bastards he is killing to another world. He curses his bad luck for not being able to fulfill his revenge because of it, but much to his surprise, there is something much better than having his revenge waiting for him.

“Layland... Be a Demon King.”

Thus, his journey of becoming the unparalleled Demon King begins.

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Those who know me are already in the know of my “condition”—minor dyslexia. So, if you find any misspell or 'wtf does this even mean' words, I hope you can pardon me from the insult, and notify me instead.