Akuyaku Reijou ni Nanka Narimasen. Watashi wa『Futsuu』no Koushaku Reijou desu! - Chapter 147.2: Girl Talk

That lonesome night as he lays dying in the hospital, fearing of death and desiring the taste of life, his mind became unprecedentedly complex with mixed emotions.

Myasthenia gravis — an incurable disease where one’s muscle slowly degenerated until the day when one can no longer move and only tears may flow.

“Is this… dying?”

When he opened his eyes again, he had crossed over into the body of a two months old infant, right in the middle of an assassination attempt.

He was born as the illegitimate son of a noble. His name was Fan Xian; and with that name came the burden of deep political secrets and the legacy of his mother.

He understood; to survive, he needed unparalleled strength, money and political power.

To a new world with the luxury of a new life, so named; Celebrating the Remaining Life.

- Description from Novelupdates

Thousands of years ago, the great abilities of the three teachings of Buddhism, Daoism, and Demonism decided on a place for becoming immortal. Three thousand years ago, a Taoist was close to becoming immortal. Three hundred years ago, the Daqian Dynasty was established, and chaos is expected in another three hundred years. In this era, the path to immortality opens; a celestial swordsman freezes fourteen states with one sword, a heavenly Daoist maiden seeks eternal life, a naturally born Holy Son claims to be invincible, and a Buddhist Holy Monk saves all sentient beings.Gu Wen lives as a beggar, enters a household as a servant, witnessing the disordered world, drifting aimlessly.In a world filled with divine beings, he alone is a mortal.However, a lowly origin is not a disgrace; striving through the grand path, even as a common man and mundane son, he can still be the foremost in the world.“Mortal Gu Wen, my Dao is euqaling the heavens!”

A college student, accidentally reborn into the world of Naruto, becomes a member of Uchiha who is destined to be exterminated.

In this cruel ninja world, in the face of endless wars and exclusion from the village, what will Uchiha Qing do?

PS: Later in the book, the protagonist will develop a system of immortal cultivation. Cultivating Immortals in the Ninja World, have you seen it?

- Description from novelbuddy

She is the slow-witted idiot of the Prime Minister’s Residence. Everyone bullies her. He is the most respected and unfeeling Prince, with frightening ability and absolute envy! Together, they are conferred an imperial edict of marriage.