The Man from Hell - Chapter 379: He Was Eaten Up By Ants!

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!
With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

- Description from Novelupdates

Ryan «Quicksave» Romano is an eccentric adventurer with a strange power: he can create a save-point in time and redo his life whenever he dies. Arriving in New Rome, the glitzy capital of sin of a rebuilding Europe, he finds the city torn between mega-corporations, sponsored heroes, superpowered criminals, and true monsters. It’s a time of chaos, where potions can grant the power to rule the world and dangers lurk everywhere.

If I were to fall into a game, I wish I would fall when I was young.

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’.