Longevity Begins with Marrying a Wife - Chapter 13: Middle Qi training

A mysterious and strange world, a human civilization lacking power, and a horrible and turbulent world of human life, Luo Kai survived humblely as a prisoner. Pain and suffering honed his will. War and killing promoted his growth. He suddenly looked back. Is already one of the most powerful beings in this world.

- Description from novelbuddy

In the Kunlun Snow Palace, a sage once said, those who pass away wander, while the living cannot let go.Once the soul departs, it will wither like the autumn grass.Those who are reborn from the dead, existing apart from the mortal realm, shall be shunned by all celestial sects and smitten as undead demons.On this day, a youth awakens from within a coffin, his blood dry and his bones chilled, to find himself a century old upon opening his eyes.A single tear from a sage awaited, a constant companion, may unravel the dreams of the past.Seeking not immortality but a mundane death, not to lament with the ages over lost love and resentment, but only wishing to grow old with tenderness in this lifetime, beneath the white clouds that hold no envy for the heavenly realms.

Kaius just wanted to unlock his class - instead, he restarted the apocalypse. After years of training, Kaius has barely acquired the first two of his family’s legacy skills. Powerful and vanishingly rare, the method of creating them is a secret people would kill for. Now they might be the only thing that keeps him alive. Narrowly surviving a bandit ambush, he gets trapped in the Great Depths- a world spanning dungeon. To escape, he will have to slay one of the Guardians that defend the exits; a feat no one without a class has survived. Ever. If that wasn’t bad enough, if he succeeds he will reignite a forgotten trial that nearly ended civilization. -Runic-Tattoo Wizard/Spellblade in a world of sorcerers -Exceptional MC, with some initial Slow Burn elements -Large scope, inspired by epics such as Azarinth Healer, BTDEM, PH, and more. -Third Person POV, with a 99% MC focus -Numbers go brrrr -Attack Badger (Friendly?) -Battle maniac MC who is not a murderhobo -No harem, romance, or VR

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?