Naruto: The Wind Calamity - Chapter 831: You have too much time...

Yo, Hi! I’m Frank, I made a deal with a demon to pay me some money for receiving a guest for a few days every week.
I had no idea about what I have done.
On May 1st, Conan ‘the God of Death’ came to my house. I was forced to let him in and we get involved in a criminal case.
On May 8th, Bruce Wayne ‘Batman’ came to me. I was forced to follow him to fight crime.
On May 16th, Hannibal Lecter, The Silence of the Lambs, came to my home. I can only say that I really can’t stand my guests.

- Description from Novelupdates

(Naruto + Single Heroine Tsunade + Romance + Action)A failed author transmigrates into the Naruto world, becoming the younger brother of Konoha’s White Fang, Sakumo Hatake, and the uncle of Kakashi. He gains a cheat ability—enhanced cellular activity.Coincidentally, just before the Second Shinobi War, he participates in a Jonin meeting where he supports Tsunade's proposal ahead of Dan Kato, marking his first encounter with her.From then on, he launches an intense pursuit, winning her heart during the war.Tsunade: “Kawakaze, why do I keep losing to you?”Kawakaze Hatake: “Because I’d like to live a few more years...”Kakashi: “My uncle is amazing, I’m his biggest fan!”Kawakaze Hatake: “Keep it low-key, keep it low-key.”

A 29 year old civil employment exam student wakes up in a blank white room and meets a baby angel. This baby angel informs him that he died in his sleep due to heart disease like his father and grandfather. Remembering his mom and their last conversation he says that he will take on a series of life and death tests that the baby angel offers him. From this point on he must put his life on the line and fight in the stage called ‘Arena’. And Every time he clears a test he will gain abilities and weapons to increase his strength. All to clear the tests and get his life back. This is his story of his fights in the ‘Arena’.

After the nuclear warfare, massacres started to spread throughout the entire world. The order between humans completely collapses, and the strong eats while the weak gets eaten becomes the #1 rule.