Naruto System in One Piece - Chapter 23: A Free Lunch

She is the underworld Ghost Doctor’s only disciple, who accidentally transmigrated into the body of the main wife’s daughter in the general’s mansion. She used to be a punching bag.Now, she stepped on her dregs of an older sister, put her father’s concubine in her place, and teaches any objectionable aristocratic ladies a lesson.

Her days are rather free and unfettered. But when did that cold as ice prince from the rumors, sporting a deadpan face all day long, fix his gaze on her?
He unexpectedly fawned and pandered to her like a devoted dog?

“Go away, you rotten man! Careful or I’ll needle you like a pin cushion!”

“Wife, why are you so fierce? As a husband, I’m so scared”
….the man is all smiles as he approached, his eyes gleaming with a cunning light.

- Description from Novelupdates

"Ding! Congratulations on binding God's Chosen One. You will receive 150% of the other party's

In a world where magic is a science, Siobhan is a genius.But even geniuses need schooling.When Siobhan stumbled into the theft of a priceless magical book, she thought her dreams of becoming the world's most powerful sorcerer were destroyed.But then a mysterious spell changed her life forever...Siobhan is now wearing the body of a strange man and has a new identity—Sebastien. With a new chance for a new start, she allies herself with a local gang—secretly a revolutionary party funding itself through crime. Now, she is bound by vow to repay them in magic and favors. But as Sebastien's reputation begins to bloom, and Siobhan's old enemies still lurk in the shadows, she quickly realizes that the secrets of this world are deeper and darker than she ever could have imagined.Forced to juggle the two sides of her double life, Siobhan is determined to uncover the truth and take control of the name they gave her - The Raven Queen.

Apocalypse befell, and roommates performed a skyward ritual.As the fog descended, the Book of Blood Spirit appeared in the hands of all survivors, and only those with a Contract monster could survive.Su Han directed his gaze to the neighbor who had already mutated and twisted, silently pulling out a gleaming fruit knife...Grotesque meat corpses, giant spiders with gaping mouths, eyeballs enveloping the city, one-eyed sharp-toothed hand monsters...Civilization fell, cities shattered, and all humans became meat for the monsters. There was only one way to survive:Use monsters to fight monsters.