Eating Melons in the Police Station - Chapter 45

More than ten years later, this sentence gradually spread in Elbaf Continent:

Never use magic to deal with tyrants, because you will find that he will return your spells to you thousands of times after being strengthened by countless magic specialties.

This is the story of a dragon-shaped self-propelled fort that keeps doing things in another world.

There is nothing that one magic can’t fix. If there is, then there are more. ——Izawa

- Description from novelbuddy

In a world where black holes, magical talents, and formidable hunters form the fabric of everyday life, Ethan Cross—a freshly graduated student with an uncertain future—once believed he would lead an ordinary existence like everyone else. However, everything changed when he awakened a seemingly feeble and inexplicable ability known as “Coexistence with Darkness.” No one took his talent seriously—until a catastrophic dimensional rupture unleashed terrifying creatures known as the “Demons of Corruption” upon him.On the brink of death, the pendant he had inherited from his father suddenly activated, summoning three dragon girls—beings of unimaginable power, yet with complex and rebellious personalities. Cursed in the past and trapped within that pendant, these three dragons have now become inexplicably bonded to Ethan. The twist, however, is that they neither recognize him as their master nor believe he is worthy of such a union.Now, Ethan must unravel the mystery of the darkness within him, learn to control his burgeoning powers, and find a way to tame these proud dragonesses—forces that could either aid him in his quest to conquer the underworld or lead to his ultimate downfall.A power that no one had believed in has become the key to mastering the shadows. Can Ethan harness it without being consumed by the darkness?

Long Fei, a cross-timer and doujin, is an otaku who traveled to another world. In the original world, he was an otaku fan of Gundam and military science fiction.

He died in an accident and was reincarnated into another world. The Gundam works he had read before his death and the techniques in various military novels could be brought to another world.

How would he use the Gundam that Long Fei created? What waves can be caused in this different world?