The Protagonist's Sister Is Actually The Strongest - Chapter 5: The Protagonist

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

Kakashi has lived a sheltered life within the protective confines of a barrier, which shielded them from the dangers that lurk outside. Raised by his devoted mother, Ako, and loving sister, Tokah, he only know a world of happiness and joy. Living in a world where he thought nothing could go wrong.But when a group of men invades their home, everything changes. In the brutal assault, Kakashi witnesses his mother's tragic death, a moment that shatters his naive understanding of safety. While his sister manages to escape, Kakashi is captured and subjected to experiments designed to exploit his hidden powers.Years later, amidst the ruins of a collapsing facility, granting Kakashi a chance at freedom. Rescued by an academy dedicated to training gifted individuals, he discovers not only the extent of his abilities but also the resolve to seek vengeance against those who tore his family apart.Driven by the desire to reunite with Tokah and avenge his mother's murder, Kakashi embarks on a journey filled with action and self-discovery.As he navigates the treacherous underbelly of a world rife with superhuman conflicts, he must confront his own problems while mastering the very powers that once made him a target.