Toaru Majutsu no Index: New Testament - Volume 12, Epilogue: End of the Extremely Passionate Quickening — CRAZY_1st_cry.

One day, Song Shuhang was suddenly added to a chat group with many seniors that suffered from chuuni disease. The people inside the group would call each other ‘Fellow Daoist’ and had all different kinds of titles: Palace Master, Cave Lord, True Monarch, Immortal Master, etc. And even the pet of the founder of the group that had run away from home was called ‘monster dog’. They would talk all day about pill refining, exploring ancient ruins, or share their experience on techniques.

However, after lurking inside the group for a while, he discovered that not all was what it seemed…

- Description from Novelupdates

Hitoshi's life sucked and then a truck made it even worse.But death wasn't the end. He wakes up in a fantasy world as a slave, expecting more of the same bad luck. Then a maid from the super-rich Aoi family buys him to work at their huge mansion. Finally, a break, right?Wrong.Sure, the mansion is amazing. The food is great. And yeah, the Aoi family treats him way better than he expected. But something's... off. Why do they watch him so closely? Why does everyone get weird when he smiles? And why do bad things keep happening to anyone who gets too friendly with him?Hitoshi just wants to be a good servant and make everyone happy. He doesn't realize that his kind heart and helpful nature are stirring up something dangerous within the Aoi household. In this new world, his greatest talent might become his biggest problem.They say no good deed goes unpunished. In the Aoi mansion, every act of kindness pulls him deeper into a web of obsession he never saw coming.“Reincarnated into Madness: Yandere Family's Unwanted Slave” is a story about second chances, magic, and what happens when being too nice leads to some seriously creepy consequences.

In a romance novel called “The Secret Lovers of the Academy” the male lead would often torment his fiancée–but wait, why did she cross into this world to become his fiancée, the villainess, instead of the heroine?