Reborn in Hunter x Hunter but it's feudal Jappon?

Emperor: "What do you mean there exists another continent beyond the vast sea around Jappan? What do you mean... they call 'Nen' something else?" Orochi Clan Patriarch, gripping his son's shoulder with bone-crushing pride: "You are my pride and joy... the heir who will unleash our Tenketsu upon this decaying world." Onmyoji Supreme Elder, sensing a storm of spiritual power: "Such dense, such fearsome Nen... yet it feels ancient. As if it remembers epochs our scrolls do not." Hidden Cloud Shinobi Matriarch, her smile a hidden blade: "A boy who knows the value of secrets? I'd gladly join you on your journey... if you pay the right price, that is." Waking up not as a hero, but as Ryugo Orochi, the sickly youngest scion of a famed samurai clan in a feudal Jappon, Ryugo has one advantage: the memories and ruthless calculus of a modern mind. And one all-consuming goal. Immortality. Strong AU. A story of ruthless ambition, world-building mystery, and strategic Nen mastery in a Feudal Jappon unlike any you know.