Naruto System in One Piece - Chapter 59

The world had been in chaos for over three hundred years.In the Central Plains, singing and dancing never ceased, foreign tribes sharpened their weapons and fed their horses, Sword Immortals roamed the Martial World, and famed generals quelled unrest in all directions.Five years before the great upheaval, the young Pharmacist Li Guanyi committed murder on a rainy night.At last, he opened his eyes and saw this chaotic human world.Underneath the hooves of horses lay piles of bleached bones – famed generals, beauties, the Martial World, Divine Weapons, commoners, Dharma Forms.Since ancient times, only white bones and yellow sand remained on the fields!Confucian Scholars, crushed beneath iron hooves; Buddhas, swept away by long spears!“I, Daoist Li Guanyi, invite this world to its death!”

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

Lin Yu traveled to the world of royal beasts, obtained the collection book of God’s pet beasts, and contracted fallen angels at the beginning.

And obtained the talent of devouring, which can make pet beasts devour and evolve infinitely.

Everyone looked at the fallen angel with twelve wings and a height of 1,000 meters filled with darkness, dumbfounded.

“Can you tell us where all your beasts are contracted?”

“My friend gave it, and I picked it up.”

“Isn’t this figure too big?”

“Maybe she ate a little too much?” Lin Yu scratched his head embarrassedly.

- Description from novelbuddy

When she woke up, Lake returned to the classroom of the third year. The classmates were in class with swords and sticks, and the teacher became a female Taoist.
The little fat man in the back seat, how to put two big hammers under his chair.
Rick found this to be a global era!

- Description from Uukanshu (translated)