Illusions, Lies, Truth - Side Story: Slay; Eliminate

I traverse along the pathway of darkness and imagination…

Wendy Waltz, a diehard anti romantic! Though born as royalty, she had been neglected by her father and bullied by her stepmother and younger sibling. To make this worse, she had been betrayed by her lover. She throws away her royalty and name and starts anew with a new name and a strange power! But who is this Head of the Imperial Guards, Lard Shroder, who keeps appearing beside her?

An ordinary youth living in the year 2050 in the Western calendar accidentally came to a fantasy world created by the collision of magical elements and supernatural technology at the other end of the dimension…

- Description from novelbuddy

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.