Concubine's Stunning Daughter : Ghost Emperor Please Be Lenient! - Chapter 46

Some say reincarnation is a blessing, but for me, it's a dreadful curse. Cursed with endless reincarnation, I've been reborn as a villain 137 times. And all 137 times, I've been toyed with and killed by heroes who are far more cruel than the said villains... If I can't win no matter what I do, then I'll crush those so-called heroes at their very roots. - Quality Fan Translations, Made by Fans for the Fans - Villain Takes Over The Academy

Exile Ren?

The start is hell mode?

Fortunately, there are crossing benefits, and it is still a stitched monster sandbox game system!

Liver Emperor Ren? Hamster Ryan? Isn’t this basic operation?

- 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?

After falling to my death, I woke up with two bodies?!Reincarnated as both a humble commoner boy and a privileged young noble girl, our protagonist enjoys their new chance in life with two different perspectives. Although they only wished for a peaceful life, the world had other plans in store, presenting them with a few unexpected obstacles along the way.Now, they find themselves confronted with bandits, secret evil organizations, terrifying monsters, and... romance?