Stop, Friendly Fire! - Chapter 4 part4

In previous life, she was ignorant and naive. She was a “villain” owning a horrible reputation ever since childhood. She was framed by her friend, betrayed by her beloved, and ended up alone and died miserably. When she was reborn in the 1980s, she vowed to recognize the true nature of the people around her and work diligently. In this life, she would never let her younger sister die for her again. She will be an excellent female soldier, a pious daughter, and a qualified elder sister.Let's watch how she goes all in, saving her sister from great distress. She will turn the tide and lead her family through the reform and opening-up, striving for prosperity and a better life.

It begins on the mountain.

With the glint of a knife, a flash of steel in the hands of a sworn brother. A betrayal.

Stabbed and pushed down the mountain, Zi Chen lied within the red-stained snow, left to die.

This is where it begins; he is given life by lightning,
baptized by thunder.

Those who had once betrayed him should all suffer in his cruel revenge.

- Description from Novelupdates

This legend tells the tale of the protagonist, Kuroki summoned to protect the demon king from the hero.

Kuroki, unbeknownst to him, suddenly came to another world. He was summoned by the demon king, Modes. The territory which the demon king overrules was in the midst of being destroyed because of the hero. He had no choice but to bow before Kuroki.

“Please save us, Savior Dono!”

Kuroki nodded, deciding to save the demon king due to an unexpected turn of event.

Nikola Tesla, the genius, a man who lost everything to balant capitalism and betrayal, awakens to find himself reborn as an orphan. What is this world? Why is he here? And will he once again fall for the capitalistic betrayal or pave his own way? What would happen if his genius adapts to cunningness of the society?