One Piece: Dream of Immortality - Chapter 489: A Wild Kaido Appears!

Divorced, disowned and down on her luck, Shui Anluo was determined to move on and live a peaceful life… That is, until her ex-husband somehow managed to find out about her baby. Now, he’s insisting that she should move back in with him. Soon, he realizes that he cannot live without her… But the road to marriage is bumpy, and Shui Anluo isn’t too willing to go through with the heartbreak again. Can she take back everything that belongs to her? Will she find the courage to jump in and fall in love again?

Time travelling from the majestic era after the Recuperation of Reiki, he became Kimura Kazuki, a 16-year-old high school student in Japan, one year before the Reiki Recuperation.

Tentatively, he set out to hone himself to the bone, burning candles at both ends to stockpile resources in preparation for the imminent Recuperation of Reiki. His goal was to be many steps ahead of all humanity when the time comes.

However, it seemed like fate had decided to play a cruel trick on him.

One year later, the Recuperation of Reiki… did not happen as expected.

- Description from Novelupdates

In a world fraught with innumerable dangers where living day by day is a struggle, a young man from the modern age transmigrated into such a world, accompanied by a peculiar system made for assassination.