Constructing-Style Wizard - Chapter 3: 2. Deconstruct Everything

In a world teeming with Titans, Colossals, Gigantic Monsters and Kaiju's, Erian who reincarnated makes his living collecting scraps of low-grade Defective Genetic Serum, realised he transmigrated along with his system.

Follow Erian as he grows to become the strongest Disaster Grade Titan with the help of his Titan System!

I’m in a secret, bad romance with a love dependent student—「Having a secret meeting with a student one is in charge of at school… Isn’t it exciting?」The special relationship with Kirihara that no one can know about began when I took up my post at Mori Kawara High School as a teacher.At school, she’s the serious student council president who has earned a lot of trust from other teachers, but when it’s just the two of us, she becomes mischievous, clingy, and jealous.On weekends, I cook meals at her place, play games together, and pamper her as if we were lovers.Unable to reject her because she knows my weakness, and despite knowing it’s wrong, we continue to pile up secrets little by little every day…「Sensei, my feelings of liking you have grown very strong.」As Kirihara openly confronts me with her feelings, the emotions I’ve been holding back grow even stronger.Even though it would all be over if it were exposed, that sense of immorality ironically only accelerates things further—

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

“I hope you don’t fall in love with me, because I won’t be taking responsibility,” warned the young man. “Don’t worry, I won’t fall in love with a body double,” the employer dully replied. Yet, both of them forgot what they had said.