Martial Arts System - Chapter 378 - Silver Ring

“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...”

Known as the country’s top onmyoji, Yuuma Kisaragi, who lived to the age of 99, awoke to find himself in an unfamiliar forest. A voice echoed in his mind, revealing that he had been reincarnated into another world at the age of 20.“Good morning, Master. Skip the greetings and please defeat the goblin in front of you.”The voice belonged to a skill acquired during reincarnation called “AI,” designed to assist Yuuma in his new life. When the skill, AI, took over the form of a golden-haired fox yokai, the familiar shape of Yuuma’s shikigami, he decided to embark on a new life alongside AI-chan.The onmyoji and AI-chan’s second life began, tackling various challenges and formidable enemies with the strongest spells and shikigami.

This is an extremely difficult game, if you don’t have enough skills, don’t even think about going out!

- Description from Novelupdates

Roy died during a war against the Evil God Cult, but somehow, he returned back in time to 30 years in the past where he was just a boy who awaken his summoning magic.