Summoner: Monster Girl Harem! - Chapter 133 3: Embrace Of Death

Witnessing her boyfriend cheating on her with her bestie, Shiyao was so angry that she went to a pub for fun and met a man, who was really a piece of work. After a crazy night she fled away, but was embarrassed to know that the man she slept with was her boss You Ze.
Jesus, give her a break!

- Description from Novelupdates

Mira is determined to be a botanist—no matter how dangerous or violent it may become. Mira made two requests upon entering the multiverse: a botany class to further her research and to be dropped off in an isolated forest far from the violent god-rearing system BS going on. She was granted both—but not in the way she expected. The system abandoned her in a hellishly dangerous forest—where she earned a rare class that excelled at killing things.

After being betrayed by her fiancé and her cousin sister, she accidentally rescued an elegant but indifferent young master. Never did she expect to marry him and surprised many!

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?