City's Best Divine Doctor - Chapter 34: Betting

Blue Learley, a seventeen-year-old girl, lived in a small town with her parents and two brothers. Everything was going as usual until that fateful night when her life changed forever. Demetrius Easton, the merciless werewolf king, got his eyes on her and wanted her as his bride. When her own parents sold her to him, she had no way of escaping him and no one to turn to for help.***“I don’t want to stay away for too long. Sometimes I fear the bird might fly away.”“The bird doesn’t have a home. The outside world is dangerous for it. And besides, the bird has already found its freedom inside,” I said. “The bird won’t fly away.”‘So you don’t have to cut its wings since it did not grow them in the first place. It’s okay. The bird likes the cage anyway.’

After dying, you wake up and realize you've been reincarnated as a background character who is judged as human trash.The decision to change your destiny comes instantly.Discovering that your identity isn't as simple as you thought, you feel favored by the heavens when you manage to become a powerful character.Katase: You won't fool me. I'll expose you for the pervert you are.Murayama: ...Thank you for saving us.Issei: Motohama, what happened to you? How are you so powerful?Rias: If you join my peerage, I wouldn't mind being yours.Sona: You beat me in the game. That means you're now my fiancé.Yasaka: Honey, Kuno wants a little brother.Kaori Houjou: Shinji-kun, let's go on an adventure.Kaede Kazama: Shinji-kun, thank you for saving me from that ball.Rie Sawada: Shinji-kun, I'll wait for you. You'll be my future husband, fufufufu...Changing known history and taking it in a direction not even his eyes could perceive, he didn't stop no matter what. Not even the other world was safe from his clutches.Lexia Von Arselia: My hero, and my future husband...Shinji advances without stopping.“I, Shinji Motohama, swear here and now that I will reach the top of both worlds.”

He Lang died by his own hands for the sake of his imperial younger brother’s ambition, whom he loved. He was offered to be reborn in exchange for giving up his past romantic feelings. Reborn without the burden of his romantic feelings, he brings with him a manual to new worlds. He wholeheartedly followed the instructions of the manual to complete the tasks, not knowing that the originally slag gong was blackening…
He pleaded to his affectionate Emperor brother to release him, he pleaded to the paranoid prisoner next door, but until the end he remained baffled.
In the end, he discovered that the full name of the manual was – “Slag Shou Cultivating Manual”
Σ (っ ° ° °;) っ!

- Description from Novelupdates

After a disaster, a despised son-in-law quietly undergoes a shocking transformation. With both medical and martial arts skills, a battle for redemption is on the brink of erupting...