As Sukuna in Invincible - Chapter 50: Gratitude

“A modern online novel writer who had been struggling finds themselves transported into the world of One Piece, becoming a 10-year-old child.After a series of events, Ryuen arrives at Cocoyasi Village. The protagonist possesses the Tori Tori no Mi (Bird-Bird Fruit), Mythical Zoan type, Phoenix form.After undergoing a rebirth (Nirvana), the protagonist's transformation no longer involves turning their hands into wings, and the fruit's power becomes even stronger!From the moment they reach Cocoyasi Village, the protagonist and Nami embark on an adventure, traveling from island to island, indulging in food, drink, and fun. Along the way, they also help the poor by taking from the rich, because, after all, Bellmere’s family is still...”

C-class mercenary. Started as a No Class, possessing nothing.

13 years of survival in the depths of the ditches.

I’ve managed to return to the beginning, but…

Upon meeting the girl who would become her adopted younger sister, the duke’s daughter Christina regained memories of her previous life. Through those memories, she learned that her new sister, Mishuli, was the heroine of a certain story. And though the story depicted a Christina who abused her sister, the real Christina turned into a siscon who spoiled Mishuli to no end.