City of Sin - Book 3, Chapter 36

What was originally an ordinary day, suddenly became a historical turning point. Enormous, mysterious Cubes appeared all over the world without warning and as if Judgement Day’s spears, inserted themselves into the blue planet.

From inside the enormous Cubes, endless streams of monsters gushed out alike raging tides, utterly defeating the unguarded armies of each state in the blink of an eye.

In order for humanity to preserve its final embers, the heads of states issued orders of retreat, to no longer attack the Cubes but rather to cling to remote cities, which they turned into self-sufficient survivor bases and around which they built 100-meter-tall Walls of Life!

Many years later, while bearing the heavy weight of history, the first expeditionary force brought back a world changing piece of information. The Cubes possessed exceedingly high intelligence and they regularly transmitted mission instructions to humans nearby. The mission rewards were incredible.

Since then, humans rushed out of the confines of the walls and once more set foot on the wasteland!

- Description from Novelupdates

Lu Mingshu had never believed in fate.

That afternoon, Roland received the most absurd gift imaginable—his stepmom handed him a System literally.That’s right. Not a game console. Not money. A real, cheat-like System... the kind usually reserved for transmigrators and chosen ones.Except Roland had transmigrated eighteen years ago, and nothing remotely “chosen” had ever happened since—until now.The catch? It wasn’t just any System. It was the “Mother's Little Tasks” System, formerly owned by his doting (mysterious) mother. And its first mission?[Mission: Go on a blind date.][Target Options: Yukino Yukio (Mom), Yukino Haruno (Elder Sister), Yukino Yuki (Younger Sister).][Warning: Once locked, your chosen girl can never marry anyone else.][Reward: 1000 Points, one self-selected supernatural ability from Mall]Roland: “...What kind of twisted matchmaking app did I just inherit?”After reading the mission, Roland was stunned. An arranged romance at 18 was already bad—but a binding rule that prevented the chosen girl from marrying anyone else? What if he failed the mission? Would she be alone forever?“And this is supposed to be a System?”“Mom! What the hell is this mission?” Roland asked, his face darkening.“It finally triggered! All those Points I spent transferring the System weren’t wasted,” his mother replied cheerfully, ignoring his outrage.“You set this up? Why?”“You’re nearly an adult and you’ve never even dated. Of course I’m worried.”“I’m only eighteen! I have college entrance exams next year!”“Exams don’t matter. But youth without love isn’t youth at all.”“...Is that something a mother should say?” Roland muttered. Most mothers pushed their kids to study harder—his acted like grades were irrelevant.“What kind of mom does this to her own son? And why is Aunt Yukio even on the target list? That’s just insane!”“Well~, I don’t know what kind of girl you like. The Yukino family has all three types—mother, elder sister, and younger sister—so I gave you options.”

She was a medical expert, talented and beautiful. She was reborn as his little wife. Her in-laws did not like her, her husband did not love her, and she was as timid as a mouse. She was weak and easy to bully.