After Ten Millennia in Hell - Chapter 46: Echidna (2)

With a sound of “Boom”, a lotus fell from the sky and leveled a mountain.
Is it time travel? Is it crossing robbery? Or was Gongdou in the sky kicked down from the heaven by some fairy concubine? who knows?
Is it a fool? Is it a cannon girl? Or a magic stick? who can guess?
The imperial court set up the Ninth Gate and Eight Heavenly Dragon Guards in Da Nei to investigate supernatural events and difficult cases in various places.
Lin Tingjun, the god of Babu, came to investigate the matter of the fire falling from the sky.
However, Lian Youyou, a hot-mouthed girl, was stuck to her, her dead skin and rotten face was so sticky.
The white-haired wolf demon on the mountain, the noble son who turned into a butterfly disappeared, and the palace ladies who disappeared mysteriously…
A series of supernatural cases may seem like monsters acting as monsters, but they are actually humans acting as monsters.
The difficult and miscellaneous cases are definitely caused by people, and they are caused by demons and ghosts.
Is it someone playing tricks? Or a ghost? Is it a monster? Or be a monster? who cares?
Just as long as the people who eat melons express excitement!
After checking, why did Lin Tingjun and the other eight gods have their own goals and stories? Then who is she, Lian Youyou?
The ancient dimensional monsters are ready to move again, eyeing the earth!
Divine matters, demonic matters, monster matters, and human affairs are not as important as Lian Youyou’s protecting the earth!

- Description from novelbuddy

There are a total of seven sins, and a revelation is made to a young man named Alex that he is destined to become a demon lord, more especially a demon lord of sin called LUST.

It's not like he can change that and because he always knew something about himself was different—not in a physical sense, well, maybe a little—and not in a mental sense—but rather because he is thrown into a demonic war that compels him to accept his new reality.

He was only aware of a difference in himself. Relating to him and the ladies who are drawn to him... Well, it was more or less like he was a magnet in front of all the girls, and all the girls were drawn to him like a metal.

Xue Xi is forced to fall in love at first sight with this dangerous man on their first meeting. With death being the only other option, she makes the first move:

I found myself lost in a different world, the characters I once read about in web novels were in front of me, harassing me, ruining my damn day. Also, a shitty system that asks you to do strange quests. But you know, the only good thing about all this: I have a beautiful face, it's nice to look in the mirror... ha, ha... I'm going crazy! How the hell am I going to survive in this damn world?tring![System Notification]- [Mission]*Participate in the NOVA Academy entrance exam[Compensation: ??][Failure: System loss]