MTL - Since 2000 - ~ 2 books recommended

I opened my eyes to find myself in another world. For some odd reason, I ended up as a sword. Before my eyes laid a plain full of magic beasts, and so, I launched my body and flew in search of a partner, a wielder (females only).

Hello, welcome to join the scp foundation, as a D-level personnel, you will get the following benefits:

First, you will get a unique identification number printed on your brand new orange clothes (prison uniform), such as D-213.

That’s not enough, you will also get a brand new name, which you will use to communicate with each other in the future! Like Billy-D.

As a D-Class, you just have to satisfy your superiors, and they’re good guys with guns! They will help you to have friendly interactions with all kinds of safe creatures (help the ten-meter killer lizard clean the room)

In order to protect your health at all times, our infirmary is always open, even if your work here is as easy as taking a walk!

When you’re done with a D-Class for a month, you can go home (and be shot), no matter what prisoner you were-

Don’t wait any longer, come and join scp!

- Description from novelbuddy

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

Sam unexpectedly acquired a dating simulation game named “The Female leads Truly Loves You”. He was quickly captivated by the game, which featured numerous beautiful female leads.Crucially, it was a harem-style game where the mc could maintain romantic relationships with various female leads and engage in sexual relations with them.Just when Sam thought achieving sexual relationships with these female leads was the game's goal, the ending shocked him profoundly.When all the female leads discovered the male protagonist's love for multiple girls, they exhibited inexplicably insane behavior.True to the game's title, “The Female Leads Truly Loves You”, each one wanted to possess the male lead exclusively. The crazed female leads resorted to extreme measures, killing the male protagonist.They dismembered his body and preserved it in formalin.They decapitated him and kept his head by their pillows to accompany them in sleep forever.They drained his blood to create a specimen, ensuring they could see their beloved male lead every morning....Realizing his fate would be death, Sam chose to avoid these female leads. However, they seemed to possess magical abilities, always finding him using various means.Fortunately, Sam had a system. By thoroughly conquering these female leads, he could avoid the deadly ending and even gain enhanced abilities.