MTL - Interstellar Spell Carder - Chapter 114 strange anonymous letter

Skyler's story was typical. He was publicly labeled a waste with no future as a Light — awakened individuals capable of wielding elemental powers. He thought that would be the end of it. But no, apparently that was not the case.He was teleported to the 'Battle Royal' to fight, even though he had zero powers and his age and potential were 100% ineligible!To make matters worse, he was not even the protagonist or transmigrator! He was just a freaking side character destined to die young in the story! And his death served only one purpose — to bring his sister closer to the protagonist!What a pitiful ending, right?However, unbeknownst to all, he wasn't meant to die but to become the best in two other realms, and they had altered the fate of that powerful King. Yet, there was a tiny problem — he didn't remember how he became overpowered in his past.

Yu Zhengdu joined a small start-up company that claim to offer “life management services”……as a programmer.

On his first day in office, he received a phone call from a stranger: “Hello, I received a text message from your company that informed me of my reincarnation tomorrow……”

Yu Zhengdu: “……??”

Shang Que, the beautiful little boss, said, “New employee, welcome to the Hell organisation in the human world. A thousand years ago, I was known to the human world as the Ghost King of Luofeng Mountain.”

Yu Zhengdu: “……??” From then on, he was incredibly distressed about the development of Hell.

- Description from Novelupdates

In the blink of an eye, the teachers and students of an entire academy unexpectedly transmigrated to a primeval wilderness rife with danger.University student Han Ning, by virtue of a panel in his hand that can add points to Soul Beasts, slaughters all in his path in the treacherous Otherworld.

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