As Sukuna in Invincible - Chapter 41: Complicated

The protagonist of the world where Lev Razanov lived had already achieved his happy ending. Meanwhile, the world continued to move forward. Until the protagonist betrayed humanity.[You have been killed by the main character.][Hero’s System successfully installed.][Do you wish to return to the past?]Lev was given a chance to return to a time when the story of his favorite novel had just begun.Although he was destined to become an extra villain—a pawn of the pawns serving the real villain, he vowed to end the lives of anyone who had caused him suffering.[Hero’s System inherits your desire from your life on Earth—the desire to do good.]“Who said killing your enemies is an evil act?”[You gain +10 kill points.][You gain +10 heroic points.]***Additional Tags: Second Chance, Past Play a Big Role, Game Elements, Handsome Male Lead.(Third Person Limited Pov.)

He rose from abjection and achieved eternity in glory.
He embraced the prettiest beauties and killed the strongest opponents.
He was able to shift the clouds into rain and cover the sky with one hand.
He could overrun the entire world and go anywhere as he pleased.
He pacified wars and held the world in awe.
He was matchless in the world.
However, his hair turned white overnight for his beloved woman and he was on the verge of death.
He was surrounded by enemies who were trying to take his life.
He struggled his way to become mighty and fought for everything he cherished.
For this age, he was the only king of the Dark World.
His name was a byword for might.
As a man living in the world, his only ideal was to pursue brilliance.

- Description from Novelupdates

In the waves of steam and machinery, who could achieve extraordinary? In the fogs of history and darkness, who was whispering? I woke up from the realm of mysteries and opened my eyes to the world.

On a harsh rainy day, a high school student without any particular special skills, Usato Ken, got dragged into another world summoning with two others; a good-looking guy and a beautiful girl, both of whom he strangely started getting along with just today. As an especially talentless individual that didn’t stand out, he thought that the others would treat him like he was useless. However, they were unexpectedly kind.———“Maybe things will be fine?”Usato who found hope in another world thought that, but the reality was different. He had a certain magic talent hidden within him and he was forced to fall into hell under the name of “training”.