The Insider System - Chapter 38: Mastering Alchemy

The people of Dafang village all say, the personality of the Lian family’s eldest daughter changed dramatically after her engagement was cancelled by her fiance’s family. She became extremely forceful and unreasonable. After hearing this, Lian Fangzhou secretly thought: Forceful? My parents are dead, my little brothers and sister are still young, with no one lending a helping hand, there are too many people looking to bully us showing up at my door! There’s still the most shameless pair of uncle and aunt eyeing our few acres of land, and even scheming to sell me off as a concubine! Treating my siblings as servants at their beck and call! If I was not forceful, how would we be able to live in peace? Don’t tell me that I should act like the previous Lian Fangzhou and die from extreme anger? In order to quell this bunch of demons, break out a wide path to walk on, angelic faces are useless, only the tricks used by malevolent spirits are the way to go!

- 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.

“It’s finally here,” said the man with the sword in an echoing whisper.

“The Tower of Choice, the last 100 floors!” the band of five exclaimed in unison.

Angelica came down from the altar with a dull look, seemingly annoying.

Then we looked around.

“I tell you once again, but you’ve had a lot of trouble in the meantime. I couldn’t have climbed to the 100th floor alone without you.”

Thud!

One by one, they fall to the floor.

Angelica’s dagger pierced my neck, and I felt a darkening in front of my eyes with a tumultuous rage. My awareness faded, from my senses, from everything else. After that, everything was eroded by profound darkness.

The world’s worst offense, is called Love.