One Piece : Brotherhood - Chapter 70

In the winter of Taikang Year 3, a girl pays a visit to her future in-laws, the Ning Family of Beiliu, Yangcheng.

After her engagement was denied, the girl decided to hang herself in front of the Ning Family to show them her sincerity.

When the girl who had died opened her eyes once more, many people’s fates were changed forever.

- Description from Novelupdates

In this world, orphans or just anyone without any hope for this world can apply to become a “walking target”. Their sole purpose is to be a practicing dummy for the students of the sect who train to become “Demon Hunters”. These students need “walking targets” to test their training on living, walking beings of flesh and blood.
In exchange, they will be provided with food & shelter.
Their existence value is lower than a slave, but if they manage to survive a few years they can receive a life long pension.

Xiao Han is such a “walking target”. One time he witnessed a powerful Demon Hunter disposing a demon. When the demon died, a fragment of the demon that managed to escape entered Xiao Han’s heart. No one saw that, and even Xiao Han himself only felt some discomfort for an instant.

But that thing in his heart soon gave Xiao Han visions, and the first one is of a cultivation method which allows Xiao Han to absorb damage to enhance his body. A perfect cultivation method for a “walking target”.

- Description from Novelupdates

For ten thousand years, the invincible Emperor Xu Lai, descends to the Earth and takes on the role of a stay-at-home dad.Anyone who dares to bully his daughter would face his wrath!Xu Lai asked, “My dear daughter, when you look up, what do you see?”“Nighttime, the stars.”“That's not just the stars, it's the empire I've built for you. In the future, you'll rule over billions of galaxies, you'll be the Empress of the Immortal Realm!”“Dad, you're bragging again. You can't even give me a little brother or sister,” Xu Yiyi pouted.“...”

Transmigrating into a fantasy world, starting as a typical rich and handsome guy, he has a useless main character fiancé, a sister who knows the future plot, and a distant cousin who is the reincarnation of his nemesis, the Nine Heavens Mysterious Maiden.He becomes the final boss in a female-oriented novel, forcibly killed by the plot?Although he has a system that allows him to become stronger by binding with geniuses, Jiang Minghan states that as a gentleman who likes to stay calm and friendly, he just wants to be good to others and doesn’t want to be a villain.To avoid the fate of being overpowered by the female leads in the future, he can only walk further down the path of a villain.But unknowingly, when did he become the source of darkness, disrupting the eternal heavens?