He's My Fiancée ! : I Went Back To The Past and You ! - Chapter 189 - 188: Different Than Amateur

Xia Yan passed through to the world of Bleach and became an eleven-year-old boy. He was rescued by Renji and Rukia in the Seireitei, and he was studying at Shin’ō Academy, and he was a student of the same class.
He is a top student of the Shin’ō Academy, and he is vying for strength by various teams. In the end, he has entered the first team of secret mobile maneuvers.
He will use punishment to kill every person who tries to threaten the martyrdom and protect his loved one.

- Description from Novelupdates

There is only one Magi Craft Meister in the world. After the death of the last Meister over one thousand years ago, Jin Nidou was transported to another world in order to succeed her will.

Abandoned by Fate, but Chosen by Chaos.A world where magic reigns supreme and the mightiest wizards stand at the apex.A world where one’s mana affinity, if one even had it, determines one’s status in society, whether one could soar through the skies like a dragon or remain grounded, scraping by like rats or chickens.This was the world Hal Fennec was born into.Raised in the poverty of a border village, Hal had one wish: to give his mother a better life, one free from the constant fear of beast attacks and invasions by the Fellkin.But fate seemed to be playing a cruel joke.Despite being the brightest and most confident among his peers since childhood, Hal turned out to be barely qualified to become a wizard.His natural talent, contrary to his expectations, was nowhere near enough to fulfill even his modest dream of a decent city life.But then, just when his final hope was snuffed out and the future seemed gray and bleak, a twist of fate—or more fittingly Chaos—granted him a system that would turn everything around.

Eira Kingston, a feared assassin, never imagined that death would lead her to transmigrate into the body of Ephyra Allen, the disgraced first daughter of the once-powerful Allen family. But what shocked her even more was the soft mechanical voice in her mind, addressing her as “master” and informing her that her soul had returned to its original body.Eira dismissed the strange voice, thinking she was having a post-death hallucination. But waking up in a hospital, with memories that weren’t hers flooding back, she was forced to confront the truth.Ephyra’s life had been nothing short of a nightmare. Despite being the legitimate daughter, she was labeled a bastard, shunned by all, and overshadowed by her scheming stepsister, who had stolen the love of her father and her betrothed. To make matters worse, the wealth and status the Allen family enjoyed were all thanks to Ephyra’s late mother, and the only reason she hadn’t been discarded entirely was due to her mother’s inheritance, locked away until she turned eighteen.But Eira wasn’t one to be defeated by circumstances. If she was going to live Ephyra’s life, she would do so on her own terms. She would destroy those who had caused Ephyra pain, claim the inheritance that was rightfully hers, and find out who was behind her own death. Because if there was one thing Eira knew how to do well, it was to survive—and make her enemies pay.However, being a high-schooler with nothing to her name wasn’t enough. As Ephyra, she’s powerless, but as an assassin, she’s lethal. Still, even that wasn't enough until she became the contracted wife of Lyle Aelion—a powerful, enigmatic figure in the business world with a secret illness. And it turns out, the only thing that can relieve him is her scent.