Rise of the Alchemy God - Chapter 2: Garret

The idiot Long Gen pretends to be a pig and eats a tiger, takes advantage of the girls in the village, travels across the countryside and forests, monopolizes the beauty and coquettishness, and achieves the legend of “Dragon Gen”. There is a widow in front of the door leaning on the door to watch, and a sister-in-law next door looking through the screen window… This book is determined to be a stallion, with the goal of pushing down and being pushed.

- Description from novelbuddy

Suddenly a high school student Subaru Natsuki has been summoned to another world on the way back from the convenience store. With the biggest crisis of his life being summoned to another world and no sign of the one who summoned him things become worse when he is attacked.

In the territory of Zhao State, there are Liuxuanmen of the martial arts sect of Jianghu.

Su Yu became a handyman disciple who was just getting started.

Having obtained the sign-in system, he signs in at different places every day, and there will be various rewards.

Sign in at the center of the training ground and get the reward [Jiuyang Zhenjing]!

Sign in on the cliff near the residence of the handyman disciple and get the reward [Millennium Snow Lotus]!

Sign in in front of the sect library and get the reward [Lingbo Weibu]!

…

In this way, it was not until decades later that Su Yu discovered that he seemed to have surpassed the peak of martial arts and reached the level of cultivating immortals before he knew it…

Ninety-eight years later, a martial arts devil who was born out of nowhere made waves in the territory of Zhao, and no one in the martial arts world was his opponent.

Until this day, the martial arts devil killed Liuxuanmen and met Su Yu who was sitting outside the library, basking in the sun on a rocking chair…

- Description from novelbuddy

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?