Angry Harry and the Seven by Sinyk - Chapter 20 - Twenty – Potter Holdings

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

It's been 25 years since the apocalypse, when the world we knew changed forever. It was then that terrible monsters appeared and some of humanity evolved to fight them.Seraphine a 18 year old citizen in Newber, was living a peaceful life with her parents, learning at the Academy, to get a nice job within the government. At least, until everything turned for the worse and she ended up as an Evolved in a destroyed city.

The poor Commandery Princess is down and out. Her father died when she was young, and her mother passed away not long ago. Her grandfather, the only one she can rely on, is now at death’s door from his illness. Faced with the merciless uncle, the greedy aunts, as well as cousins competing to present the model of the worst relatives, the Commandery Princess could do nothing but feel depressed in heart.

Kusumi Chiharu gets a message one day that he has been selected as a Monster Tamer, and he is prompted to select his first partner. He thinks little of the message until he receives a giant package the following day. He assumes it’s the porn books he ordered, but the huge box ends up containing the unconscious body of a near-naked girl! She’s a ghoul named Zonmi, who intends to fight beside him as his partner.

However, it turns out that other hot girls at his mostly-male high school are also magical entities, and Zonmi may not be the only one who wants to fight by his side!