In the MCU/Marvel with the Omnitrix/Ultimatrix - Chapter 13: Finally... Rest

Before going to college, an ordinary high school student went to celebrate and got drunk. When he woke up, he found himself in a completely different world. There was a big sect, the approaching sect entrance examination, a slum where his body’s previous owner lived, and a shared memory about a missing young girl.

When he got tangled in a fight with a few punks in this different world, he fell off a cliff and miraculously found himself still alive, with two more voices ringing inside his head. They were Sword Master and Saber Master. In the company of them, he continued to find out more about this whole new world. He took the sect entrance examination, entered the sect, met a strange man in black, and even participated in a major competition of the sect to have a chance to win over his peers!
In this whole new world, he was born again and got to explore the fantastic martial world!

- Description from Novelupdates

“You call yourself a hero? After your greed killed my sister?”What would you do if all of your friends, everyone you ever loved besides your sister, died in front of you?What would you do if, because you were weak, everyone hated you and considered you a Wasted, someone who hurt humanity's chance to survive extinction?Adam continued fighting despite this abuse, because he still had 1 simple goal: even if he was nothing more than cannon fodder or wasted potential, he would keep his sister safe.But then, it wasn't the Kaiju or apocalypse that killed her. It was the Exalted, the strong, the heroes of society.The people he was supposed to praise were the ones who took his last hope in life away before killing Adam as well.So, when he regressed with a villain system that rewarded him for killing Exalted...[First Exalted killed!][Artifact: The Mantle has upgraded to level 2!]

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’.

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!