Mitou Shoukan://Blood-Sign - Volume 2, Prologue

He is high above, the mysterious and terrible King of the Wild. With one glance, he can see people’s romances. He hates women to the extreme, but at his first glance of her, he dotes on her and spoils her.
She is a humble transmigrator, a miracle doctor who doesn’t care for the many handsome men around her. She only wants to become strong, to be worthy of that god-like man. But when she’s finally sure of her feelings, she finds out she’s already been married for years…
……
When wronged：
She uses strength to hit the big handsome iceberg-like man in front of her eyes. “People say that I’m not good enough for you, but it is you who is an old cow eating tender grass!”
A man seizes the main point and laughs like an evildoer. “This husband has to eat the grass to confirm if it is tender or not!” He puts out the red candle……
……
The world says：
The barbarian king has no heart and has no passion.
A pregnant woman very miserably thinks,” If he has no passion, then who is responsible for this big belly?”

- Description from Novelupdates

Ye Qinghan, young master of the powerful Ye Family, gets ostracized when his peerless father meets an unfortunate end. Lacking strength and in a bid to live a Purposeful life, he suffers through the unending ridicule, bullying and torture dealt to him at each turn. However fate is a cruel mistress and offers only pain and misery with no end in sight. Broken, weak and distraught, Ye Qinghan embarks on a journey to usurp the hands of fate and attain strength to protect his own.

The world was once at war with 10 alternate worlds. This was known as the Concept War and our world won 60 years ago. All of this was concealed so no normal people are aware of this fact in the current time.

After the death of his grandfather, the high-school student Sayama Mikoto is suddenly summoned by the giant corporation IAI. He learns this world is headed for destruction due to the acceleration of the Minus Concepts. To prevent this, negotiations must be undertaken with the survivors of the other parallel worlds so their 10 concepts can be released.

And so Sayama is caught up in the final battle to clean up after the Concept War which left behind so much enmity.

Being taken away of all his freedom, Noah was thrown into the jail accused of a murder he hadn't committed.

This incident broke his personality permanently, getting out of the jail Noah started living as a shut-in giving up at everything.

Noah read novels as a mean to pass his time, while reading novels an particular novel caught his eyes, it's name was 'the hero of velveric fights the demon lord'

'It's a harem novel......'

That was what Noah had thought in the beginning but, it all changed at the end of the novel.

'What the Hell's with this crazy novel!'

The protagonist and all his harem members were killed and in the end the demon Lord took over the world.

It was then, after finishing reading the novel, Noah started coughing out blood and succumbed to his lung disease.

Opening his eyes Noah found himself in a body of a 8 year old kid of the Melvix family which appeared in that crazy novel.

He was known as the garbage of the Melvix family by all the knights and family members but that didn't matter to Noah. What matter is that-

'It's impossible to survive in the novel if you are not strong enough......'