Harry Potter and the Secret Treasures - Chapter 4 Diagon Alley

Perhaps it is the choice of fate. As a senior otaku, Qian Lingfeng got the “steel shell system”. However, when he swept the world with the system, became a local rich man, made all kinds of beautiful women, opened a harem, and realized the ultimate fantasy of thousands of otaku, he found that things seemed far from simple!
When the end comes, biochemical zombies suddenly come down, fierce beasts are in power, bloodthirsty zerg roam to kill the world, and human lives are comparable to dirt. Where will weak human beings go in this world? Is humanity going to be extinct? Or … can an otaku save the fate of the human race?

- Description from Novelupdates

Cale Virel was just a normal office worker.He was bored and tired of his life, waiting for it to end.And then—Bam!One night, two robbers targeted him!And instead of surrendering, he fought back!Though, in the middle of doing so—PHUCK!He got stabbed and died...He didn't regret it though.After all, he's not really afraid of death anymore.And so...He rested in peace..........Or so he thought!Cale Virel—“Huh? What the fuck?”He woke up as a young slave named Kaiser in a different world!And given another life he didn't ask for again—“Fuck this shit!”Cale, or should I say—Kaiser—“Ugh, whatever.”Decided to live it... By just doing whatever he feels like until he dies.

Ham Dani, a normal student whose hobbies were to read novels.

The Celestial Express is a train that goes from one galaxy to the next, picking up passengers along the way.Its Navigator, the one who drives it through the stars, is a god who can grant those passengers wishes.Jax arrives on the Celestial Express with no memories but a single wish—to save someone. After learning what the Navigator is capable of, he decides to go find him.To find the Navigator, he must go through TEN different Carriages, all of which contain a world of their own.And, he must do it with a restriction called Single Spell Sorcerer.