I Reincarnated As An Immortal Bat Into Another World - Chapter 38 - - Loyalty of Eclipse

After five years, Ning Xi has returned and is out to take revenge on the sister who turned her parents against her and the childhood sweetheart who betrayed her for her sister. She aims to fulfill her childhood dream and become a famous actress. However, her sister is still out to get her, and she has to avoid all her underhanded schemes.

One day, after falling into one of her sisters’ schemes, she meets an adorable kid and saves him. This is how Ning Xi found herself staying at the autistic little kid’s house to help him come out of his shell. Slowly, his father, Lu Tingxiao, starts falling for her too.

- Description from novelupdates

What would happen when someone from our world was suddenly reborn into the world of My Hero Academia with a Gacha System that rewards him with abilities, techniques, and skills from Jujutsu Kaisen? Grand epic fights and crazy shenanigans as he goes through the story to cause chaos and change the world to his liking.

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

The world was once at war with 10 alternate worlds. This was known as the Concept War and our world won 60 years ago. All of this was concealed so no normal people are aware of this fact in the current time.

After the death of his grandfather, the high-school student Sayama Mikoto is suddenly summoned by the giant corporation IAI. He learns this world is headed for destruction due to the acceleration of the Minus Concepts. To prevent this, negotiations must be undertaken with the survivors of the other parallel worlds so their 10 concepts can be released.

And so Sayama is caught up in the final battle to clean up after the Concept War which left behind so much enmity.