Warlock of the Magus World (WN) - Chapter 440

Hazekaya was just an ordinary guy… until he woke up in another world. Sounds exciting, right? WRONG!Before he could even process his isekai moment, he found himself being chased by a horde of horny male orcs.From dodging unwanted “affections”, to getting thrown in jail, to accidentally sleeping in horse crap and earning just enough to not starve. Between dealing with an ex-adventurer boss, getting tricked by his so-called “friends,” and realizing even slimes are harder to kill than he thought, his life in this new world is anything but the overpowered adventure he dreamed of. Instead of becoming a hero, he’s stuck as a low-wage wall repairman, constantly broke, and now the locals call him “Shitman.”With zero cheat skills, no legendary weapons, and a severe lack of dignity, Hazekaya is left wondering—“Why is my isekai life like this!?”

Reborn into the world of Yugioh, it's natural if my goal is to become the best duelist!

An ordinary student, a wretched peeper, a cowardly teenager with a kind heart. In a terrorist attack, he inherited the knowledge of countless elites, embarked on a path of God Jagged Tu…

He is an artist!

He is a mathematician!

He is a psychology Doctor!

He is a master of fighting!

In fact, he is a man

Taken off raw site:

A wretched, dirty young man is working during the summer when he was caught up in a mysterious explosion. After that explosion, the young man is then left with the memories and knowledge of dozens of the world’s experts.

He has changed, his heart has become cold, iron-blooded. He became a killing machine, his mind turned mechanical, calculative. Everything goes according to his plans and calculations!

In this magical, slaughterous world, a door is opened for him…

- Description from Novelupdates

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?