The Grandmaster Strategist - Volume 4, Chapter 23: A Priceless Letter from Home

Humanity had finally ended the war with the Demon Race and sealed them away, forever.However, they now have to face the treat of the Shadow World, an equally dangerous threat to their civilisation under the rule of the Emperor!Facing only misfortune from a young age, Nikolaus Reinhardt never expected anything good to happen to him.But his world completely changed when he awakened as an Ascendant, and accidentally summoned a member of the Demon Race in his house.Just because he messed around with a god damn book!

“He” was originally a weak and pitiful “sissy”. Once reborn, he became an ancient martial arts genius with both medicine and poison. The national male god.

Don’t touch anyone who belongs to her, and she will hold what is not her, and she will never be merciless when she abuses scum and face.

He is a business genius who covers the sky with one hand in Huaguo. He has a dark belly and is decisive in killing. He is the only one who turns into a loyal dog in front of her.

She kills, he sets fire. She poisoned, he silenced.

One day, the pampered and lawless Lu Xingchen said in disgust, “Brother, they all say you are my dog.”

- Description from novelbuddy

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!

I’ve had enough of being transmigrated into books.