Why the bug I wrote became a core gameplay mechanic?! - Chapter 613 - 596: The Power Was Taken Back Again

Transmigrated to a wizarding world.'But... what about the promise of wizards pursuing truth?''Why is it just a bunch of greedy people who seek power!'...Passing guests, please come in and take a look; if it's not the right fit, then feel free to leave.

In the foreign world, the martial artists dominate the world and the sword of the emperor controls the fate of hundreds of millions of lives! Long Yu, the number one killer on Earth, after dying, takes rebirth in this new world in an aristocratic family of martial artists but faces rejection because he is unable to practice martial arts.

- Description from Novelupdates

Eren Idril died as an old, decrepit, and piss-poor adventurer by the maws of a D-Rank monster. He had a lot of unfulfilled dreams and desires that couldn't see the light of the day after the light in his own eyes died down.

But fortunately for him and unfortunately for the world, that wasn't his end. Eren was somehow dived back in time when he was a mere teen, attending Lionheart Academy for adventurers.

When life gives him a second chance, Eren decides to exploit it to its fullest. Experience his vile deeds as he partakes in them without feeling the slightest bit of hesitation.

This stands at the forefront of strategy guides to Life (a shitty video game)!