Toaru Majutsu no Index: New Testament - Volume 14, Epilogue: The Time for the Cradle Comes to an End - More_Purely,More_Bloody.

Master martial artists were beings that no one can obstruct. A martial arts expert has been reborn into the body of a genius whose cultivation has been abolished and has been abandoned by a woman. Therefore, he starts cultivating the art of Xing Yi Quan, producing a solar system within his dantian. His innate talent tramples over all the geniuses, and even the geniuses among geniuses.

His powerful spirit and ruthless and ambitious nature, no matter who he is reborn into, will never change! Slaughter is instinctive, being cold-blooded is his personality, exterminating an entire family is only a means towards a goal, cruelty means infamy, and chasing after women… is just an interest.

- Description from Novelupdates

30-year-old Jo Minjoon has always wanted to become a chef. He started his culinary career late in life, however, and is currently chopping onions at a restaurant. Regretting his life choices, he wishes he could go back to change it all and falls asleep. Meanwhile, someone out there is willing to give him another chance and send him back in time. How will he use the new powers he obtained from this mysterious being?

He became a teacher at the best magic academy in the empire.
….For being mistaken for someone else.

The previous lords have committed as many atrocities as possible to fill their bellies. I, the only daughter of that house, had discovered that my servant and lover was a spy.

And as the people wanted, my life ended with my execution.

However, with the memory of getting beheaded intact, I began a new life. I was planning to shoulder the sins of my past life and become a nun, but by some trick of fate, I came to work as a maid for the current lord.

Under my former lover, whose name, age and even hair colour were all lies.