Five Years Later, She Bombarded the Palace with a Miniature Version of the Regent - Chapter 18

Xin Yun, a sarcastic young man, traveled to an unknown world by chance, but lost his chance to become the strongest because of his obsession with women... or sex. In a collision of the powers of nine powerful men, an incredible thing happened. Xin Yun was reborn back to the time when he traveled to the Isekai world. A fantasy journey is about to begin... [The comic adapted from this novel is popular all over the world]

Nagasawa crossed to Naruto Universe and was bound to Konohagakure.

If Konoha is severely damaged and destroyed, Nagasawa’s lifespan will be reduced.

He panicked at the thought of the upcoming Nine-Tailed Demon Fox’s attack , and the thought of Konoha getting destroyed left him in despair.

Fortunately, while bound to Konoha, he can obtain templates of powerful characters.

At the beginning, He got the Whitebeard template! Since it’s the Whitebeard from the Summit War of Marineford, he can use Tremor-Tremor Fruit’s ability and Haki.

Facing the Tailed Beast Ball, which terrorized Konoha Shinobi, Nagasawa leaped and shattered the Tailed Beast Ball with one punch!

- Description from Novelupdates

Grandpa Yu often repeated beside the ear of Yu Zhen, saying that he(YZ) has a soul in his body. If he doesn’t properly train in asceticism, and raise then send away the powerful soul, in this lifetime he would have to live as a bachelor. In his next lifetime he would be reborn as a lifestock animal.

Yu Zhen played on his mobile and nodded. On the surface he replied, “Uh-huh”. In his heart he laughed, “hahaha”. Keeping his grandfather in the dark was amusing so the lie was repeated for over ten years without Yu Zhen getting tired of it.

After some years, Grandpa Yu passed away and a cold-faced handsome guy came to his door in a luxury car – with a household register in his hands.

…..

Yu Zhen: The soul in my body reincarnated into someone else’s body to demand repayment, what should I do!

- Description from Novelupdates

An ordinary young man reincarnates as Adrian, the eldest son of a once-prominent noble family now living out in boonies of the kingdom. Watch as Adrian embarks on a tantalizing journey, to support his graceful and caring mother and feisty older sister, as a man should, with his seduction system.