I'll Teach You, Marianne. - Chapter 646 - Surprise Party

A college student was returning home after studying abroad for several years when the end of the world happened. A dragon appeared out of nowhere and attacked the plane he was in, thanks to an incredible amount of luck and his quick-thinking, he managed to survive the plane crash only to get stuck on a tropical island. A weird system took over the world and brought monsters to Earth. While nations collapsed and the world as a whole was being destroyed by ridiculous monsters, Leon was stuck on a godforsaken island with no chances of being rescued. What will happen to him? How will the world change while he is away? Will he even manage to return? The story, all names, characters, and incidents portrayed in this production are fictitious. No identification with actual persons (living or deceased), places, buildings, and products is intended or should be inferred.

Koi Niles has always been alone. Quiet halls and empty lunchtimes are his familiar companions. Grades matter to him; they’re his way out.Ashley Miller owns the school corridors. Captain of the ice hockey team, confident smile, and a name everyone knows. When a class project pairs them together, Connor sees a chance. But Ashley disappears, leaving Connor to carry the weight.Days later, under the harsh lights of Connor’s part-time job, Ashley returns. This time, it’s different. He stands up for Connor, turns the tide against the bullies. A simple act of kindness that feels new and warm.They share moments—short walks, brief talks, the understanding of two worlds colliding. Friendship grows where none was before.But Ashley holds a secret behind those bright eyes. One evening, worry leads Connor to Ashley’s door. What he discovers there changes everything he thought he knew.

The constant mission is getting redemption.

Shuttle though various worlds to become a variety of scum men, do a little whitewashing and become a good man in the eyes of everyone.

Redeem those who are miserable, and let them live a happy life.

- Description from Novelupdates

After the nuclear warfare, massacres started to spread throughout the entire world. The order between humans completely collapses, and the strong eats while the weak gets eaten becomes the #1 rule.