Kami-sama no Memochou - Volume 1, Afterword

He was on his way to buy some beer to celebrate his acceptance as a civil servant when he was suddenly isekai’d by truck-kun.

Damien reveals an ugly truth.His sister and only family, Ahara, leaves the house every midnight whilst he's asleep—a time that he soon discovers is when man-eating beasts named Rouges start hunting for prey.Unable to question her directly, he decides to investigate her and quickly figures that Ahara isn't human but rather, a vampire hero who saves them from beings like herself coming from a world she calls Gibbous—a place where entities like vampires, wizards, and beast shifters alike reside. What’s more, he also learns that the real reason behind his parents' death was the leader of the Rogues, who's rumored to have escaped after Damien’s father almost killed him.A series of fateful events lead to Damien’s long-lost power reawakening in him, and he finds himself with no choice but to return to Gibbous, a strange world where power means survival, and weakness leads to death. As such, Damien enrolls in an academy to train his newfound abilities with one thing in mind...Becoming more powerful.However, he soon discovers that the path to power is one filled with troubles and pain, and he isn’t alone in this lust for more at the academy. It’s a bloody competition against time and formidable opponents, and only those willing to sacrifice their comfort are the ones who can attain it.With a deadly foe lurking in the shadows somewhere and a strong desire to protect his sister, Damein has no choice but to fight.The only way is up, and he is going to be standing at the top of them all, ready to counter any enemy.

500 years ago, Chen Xi was devoured by a crack in the void and was transported into a cultivation world.

This is a time of great powers: The vast Persia, Sparta that is founded by force, Athens with its trade and business, Thebes the rising star, The ambitious Macedonia, The twin heroes of the Western Mediterranean, The rising Rome and so on.

This is an era of brilliant stars: Agesilaus II – the last king of Sparta, Epaminondas – the Rising General of Thebes, Philip II – the founder of Macedonian hegemon, Dionysius – the tyrant of Syracuse, Camillus – the Roman dictator and savior…

This is an era of contention among a hundred schools of thought: Plato – the great philosopher, Antisthenes – founder of cynicism, Pythagoras – school of number, Democritus – the encyclopedia scholar, Hippocrates – the father of western medicine, Aristophanes – the great dramatist…

What will the hero bring to the world when he comes to this age as a humble mercenary through rebirth?

- Description from Novelupdates