Elf Kingdom: Game of the World Tree - Chapter 143 - 142 You lack integrity!

She, a modern hidden ghost leader of an organization which gathered insane prodigies proficient in the various differing skill-sets. Highly skilled in medicine and poison, executes covert assassinations, viewed as insane and demonic in the eyes of people of the world. Killed in an accident, and reborn into the body of a disfigured young girl.

What? Face disfigured, identity stolen? A return to the family dim and hopeless? Her identity can be given up, her family can be forgone, but as for the one who harmed her predecessor who inhabited this same body, if she didn’t at least make them scream in unimaginable agony and throw them into a state of wretchedness, how could she live up to her demonic reputation? Endless turmoil ensues and it’s a battle to dominate over all! See how she shook the world dressed in a suit of red, her sword up against the dominant powers that rocked the Heavens! Her name spread across the seas, shocking the earth!

- Description from Novelupdates

When her father passed away, her mother married into a large family. She thought it'll be a new beginning of her life, but it only brought her an substitute marriage to a disabled husband her step-sister didn't want.On the second day of their marriage, the noble and aloof man said indifferently, “Divorce or live as a widow, choose one.”She pulled off his suit pants and touched his firm and sexy thigh, “I choose the third option!”Latter, she used her medical skills to healing and saving people, including her disabled husband, who turned out to be a hidden billionaire!Nobles and celebrities sought medical advice, flocking to her like ducks.Those who humiliated her regretted it deeply, begging for mercy on their knees.The billionaire smiled proudly, “My wife is a treasure, only her husband knows it!”She rubbed her waist and gritted her teeth, “Didn't you say that you wanted a divorce and warned me to stay away from you?”

A tree of 10,000 flowers, the world is the door.
The spells change a lot, but the hearts of the people are unchanged.

- Description from Uukanshu translation

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?

- Description from novelbuddy