Toaru Majutsu no Index: New Testament - Volume 4, Afterword

Riku Barusak is a hard-working child. Despite possessing an innate superior physical strength and having withstood harsh training she fails to unlock her talent as a spiritualist. The failure results in her being thrown away by her family.

Abandoned, the only ones that extended a hand to her were the demons, the greatest enemies of the human race. Serving under them as a soldier she becomes a weapon of human slaughter, a fiend that should never have existed.

Long Chen, a crippled youth who cannot cultivate, is constantly targeted and bullied by his fellow noble heirs. After a particularly vicious beating, he wakes up and realizes a Pill God’s soul has somehow merged with him, giving him some additional memories. Within those memories is the mysterious Nine Star Hegemon Body Art, a cultivation technique that even he can train in, but whose secrets and origin are still a mystery to him. Relying on his improved instincts as he finally begins to cultivate, he realizes a huge conspiracy is underfoot within the Phoenix Cry Empire, one involving his father, members of the imperial family, and even the Emperor himself.

In order to solve the mysteries around him, he must rely on his new alchemy techniques and the powerful but baffling Nine Star Hegemon Body Art. Countless enemies block him as he attempts to climb to the peak of the cultivation world.

Fate destined him to be only a chess piece, but he would not bow to the will of the Heavens.

“Compared to our time, the current generation just aren’t as reliable” they said, “Still, isn’t he the son of the Hero?” How annoying.

It’s been over ten years since the battle between mankind and the demons ended. The children of the heroes who saved the world are all grown up.

One of them, Earth, was a talented man, and everyone expected him to succeed his father as a warrior and defend his country, but Earth was always wary of his father’s title.

One day, Earth is shocked to find his father’s sword, which was used to overthrow the Demon King, sealed in his family’s mansion.

Because trapped within was the ghost of the Great Demon King who was unable to pass on and continued to roam the world.

For some reason, only he could see the spirit of the Demon King, and the Demon King possessed him through the sword.

Every day, forced to coexist with the spirit of the Demon King, they live a strange shared life, when the Demon King whispers to Earth on a whim.

“I have a grudge against your father. If you want to get back at your father and the world, I’ll train you. I’m free.”

Earth receives special personal guidance from the Demon King just to get back at his parents and the world.

Then, in the coming days. The hero’s parents, the heroes of the past, the first love, the princess childhood friend, the geniuses of the era, and the world will tremble.

What?! The sticking to her daily, eating her tofu (taking advantage of her ) is a cross-dresser?

Not to mention that he is the Evil Highness!! She had slept beside him, and was touched by him, what a big loss!

Ah–!

Softly on his chest, listening to his pounding, strong heartbeat, her face turned red. Her greatest desire was to be in his arms.

She never dared to dream before, dared not wish for, and thought that in this life there was no such chance. This had been in her most secret heart of hearts, she longed for his warmth, longed for his love.

Even though he had hurt her before, he had given her more tenderness than others.

Being teased, loved, laughed at… had infiltrated into her bloodstream. Love, she did not know when it had taken root, for when she discovered it, it had grown into a towering tree, no longer able to be split open or cut off.

His hug, his warmth, she would not allow him to give it to others. If they were not only for her, she would rather not have them.

- Description from Novelupdates