I'll Teach You, Marianne. - Chapter 719 - Civil War

The strongest man of the cultivation world, Yu Hua had sent the Grand Supreme Elderly Lord, Chi Hou to cultivate. After cultivating, Chi Hou was unrivaled for hundreds of thousands of years. However, he was ridiculed by the Demon Lord to be a bachelor who is as old as bone ashes and a fossil grade single dog. Not to even mention a girl, he doesn’t even have a little sister. In order to reverse the game, Chi Hou decided to kidnap the Demon Lord’s precious sister and turn her into his own little sister. He’ll first save her, then raise her, teach her magic, feed her dinner, tell her bedtime stories, and give her rare treasures. Like this, he’ll be the perfect brother. She won’t even remember her real brother.

Little sister: “What does this pervert who pulls me up every night to tell me ghost stories want to do? Cultivating to become a celestial is too hard, I want to go back to Earth!”

- Description from Novelupdates

She is intelligent, beautiful, calm, and professional. As the youngest chief forensic investigator for the past few years, her future was very bright. All of this, however, changed with a bizarre time-travel.

Hikaru found himself transported to the Pokémon world, but instead of becoming a Trainer, he was now a craftsman specializing in item creation.In an era where technology flourished and traditional craftsmanship faded, artisans were slowly becoming obsolete.However, Hikaru soon discovered something extraordinary—the items he crafted could grant Pokémon incredible enhancements and unique effects.Ancient Relic Slabs, Transparent Bells, Royal Crowns, Reins of Unity... He gradually became a renowned antique craftsman across multiple regions.Rainbow Wings, Life Orbs, Volcanic Keystone, Eviolite... He also embarked on journeys to collect rare materials, earning a reputation as a mystical traveler.Choice Scarves, Victory Armor, Purity Pendants, Shining Charms, Dream Balls...Even items from the Pokémon Trading Card Game could be crafted through his mysterious abilities. He became known as the Unbelievable Master Craftsman.Along his journey, he encountered companions just as unique and ambitious as himself—An Aegislash who sought to create an ideal kingdom.A Lilligant devoted to the cultivation of Berries.An Armarouge obsessed with the art of forging.A Magearna skilled in mechanical inventions.One day, Hikaru turned to Ash Ketchum, offering him a peculiar item.“Here, Ash. Try this.”He handed him a green die—a tool unlike anything seen before.A new adventure begins.

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?