MTL - Lord of End of World - ~ Chapter 67

An unexpected journey took a group of university students into a secret room from which, upon returning, they began to disappear one by one. In order to unravel the mystery, they joined forces, traversing heaven and earth, diving deep into seas, crossing the farthest corners of the world, and even daring to time travel, only to find that behind each puzzle lay yet another.

Oliver West never expected his quiet life to turn into a nightmare. The boy who once shared secrets and summer adventures with him has become someone he doesn’t recognize. Keiran Morrison - tall, dangerous, and devastatingly handsome - now uses that same intensity that once made Oliver’s heart flutter to terrorize him instead.Every day at Riverside High is a battle for survival. Every corner could hide a new humiliation. Every moment of peace is just the calm before Keiran’s next storm.But why does Keiran’s hatred burn so bright? What happened to turn childhood love into adult cruelty? And why, despite everything, does Oliver’s heart still race when Keiran gets close - even when he’s terrified?Some mistakes can’t be forgiven. Some wounds run too deep to heal.But sometimes the line between love and hate is thinner than you think.

A con-man and policewoman that are legends of their respective professions suddenly die, then are reincarnated and return to the Tang Dynasty of ancient China as little kids.

Accepting their second chance and forced restart, they choose to use the modern knowledge and specific talents that they have in their previous lives in order to live comfortably in this new life.

- Description from Novelupdates

Our protagonist Caam is a man from Earth that was reincarnated into this world as a demon. In order to survive, he spared no effort in avoiding the sparks of battle and without noticing it, he became strong himself.