Married To My Ex's Brother, Reborn Miraculously - Chapter 2: A silent vow

One day, Luo Jian woke up from his sleep and found himself in a locked chamber where the door and window were all sealed. A note with a few lines written on it was tacked to the wall: “Escape from this room within an hour, otherwise, you will die.”

There is a sequel called Reincarnation Night (轮回之夜) that takes place in the same universe but has different main characters

- Description from Novelupdates

s a self-professed no-lifer, Yuri idles his days away in front of a computer. This all changes the moment his life in Japan comes to an abrupt end and he finds himself reborn in the strange new world of the Shiyalta Kingdom. His new life includes everything he once lacked: loving parents, a comfortable home, and a promising future breeding and raising birds on his dad’s ranch. For centuries, the kingdom he now calls home has enjoyed peace and prosperity, shielded by friendly nations that, like Shiyalta itself, were established with the collapse of a once-great empire. War is a distant problem, relevant only to Shiyalta’s ruling families whose warriors periodically set out to join the fighting upon massive birds trained by Yuri’s dad and others. But this peaceful existence can’t last forever. Something rotten lies at the heart of the kingdom, and it doesn’t take someone with Yuri’s exceptional intelligence to realize that those distant battles will only remain irrelevant for so long.

Ten Years after the Descent to Earth of a Radical And All-Knowing System Called Arkadia, Life has changed in ways we could only surmise given we lived in a comic book. People with superpowers, Monsters, Heroes and Villains, Hell, there were even Other races coming out of the woodwork like Elves and such. Still, it wasn’t until The Extraterrestrials Invaded that things went from bad to worse.Yet, as if hope truly existed, 5000 of us Earthlings were given the opportunity to Head back into the past, only we didn’t know at the time there was a cost for doing so. By sending us back, the Descent Clock began, as Arkadia was pushed 10000 years into the Future, and it was up to us Returners to get things set back on course by changing the past to mold the Future.And I, being a boogieman of a Villian in what I dubbed the Origin Timeline, have come up with thousands of potential ways to affect my new life, like stealing popular franchises to earn some long-term funds or….hunting down notorious Serial Kills and Solving long-standing Cold cases I had been curious about since I was a teenager.

An otaku with a hobby of masturbating was reincarnated as the son of a great mage.

As soon as he was born in this life, he vowed with a goal of embracing women till his death.

That said, when he became 20 years old, the Demon Lord which was sealed by his ancestors revived, and now it is his role to seal it once again.

And that demon lord is sealed in a tower dungeon that is rumored to be impossible to capture.

However, by an unexpected coincidence, he had found out that the Demon Lord is also one of him, a kindred spirit from within,

so he joined her instead and filled several traps in the tower dungeon, and thus they enjoyed a s*x spree with all the women coming over!