MTL - The Troubleshooting Diary at Hogwarts - Chapter 73 Rain on March 11 (middle)

This world is sick, and it must be cured with swords and forged with iron and fire.To slay tyranny, to cut down the unrighteous. To overturn heaven and earth, to mold the human world.All shall begin with the sword in hand.======When the Innate Wisdom Bearer An Jing received aid from the ancient Sword Spirit, allowing him to traverse various realms, he knew that his future would inevitably lead him down a path full of hardships and difficulties, hard to be understood by others, yet capable of changing this wretched world.And on this path, he would also crush many deserving scum underfoot.“Heh heh, the Myriad Tribes of this world shall greet the birth of this epoch-making giant like me with fervent wishes. World, I'm coming to save you!”Noble Officials/Demon Sect/Heavenly Demon: “Alas, is reconciliation possible?”Elements: Chaotic times of Martial Arts, cyber cultivation, gates between two worlds

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”.

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The fallen ones, strange monsters that showed up on earth with the sole purpose of destroying everything and ruling over humans.Only one man remained during the onslaught, his name, was Rashin Montero.“Do you wish to live or die?”The question appeared before him.“Kill me assholes!”He died.A hundred years passed and Rashin finds himself alive in the future.It turned out he was saved by a stray angel, and was granted a powerful energy that allowed him to stand on equal footing with the monsters that once wanted to take over earth.In his new future, the world has been restored to what it ones was, a huge shield was placed around the world to keep the Hakiaas out.Heroes were summoned to defend the world against these monsters during the Countdown, while the monsters could not be killed or harmed, they could still be sent back to their world.Or at least, until Rashin arrived.[Blacksmith System activated. Welcome host.][Initializing core functions... Complete.][Congratulations, you have gained a new blue paint (Large sword.)][Stella blade has passed all requirements to evolve.][Evolving to human form can now be processed.][Congratulations, you have gained a unique core, your weapons can now undergo fusion.]Having a system that allowed him to craft weapons of all kind, Rashin enters this new world trying to survive while also remembering part of his memories.Not just that, he can also turn every weapon he makes into beautiful overpowered maidens capable of killing the Hakiaas aka fallen ones.

Shi Qing Xia is practically an angel.

Kind, sweet-hearted, and good at her studies, she was admitted to the top university in Taipei.

However, the living expenses for the metropolitan city were far greater than she had ever imagined, so she started to work as a private tutor for wealthy families to make ends meet.

On her first day of work, she met Zhao Yi Bo and Zhao Yi Xuan, a pair of neglected 16-year-old genius twins whose prosperous and wealthy parents heartlessly abandoned in Taiwan. Shi Qing Xia found them to be gentle, compassionate, friendly, clever, mysterious, pitiful and attractive.

But appearances can be very deceiving…

Because behind those sweet smiles…

Deeply twisted and cruel demons lurked, waiting to rip apart the wings of this angel, condemning her to an eternity of conflicted bittersweet suffering — a rollercoaster ride of a heart-wrenching, twisted, and tragic romance more extreme than what someone so innocent could possibly imagine.

- Description from Novelupdates