Fantastic Tribulation

A modern-day setting where the world has been through an event where monsters seen from RPG fantasy have appeared throughout civilization. These creatures cause chaos and destruction in their wake, and any modern means ineffective towards dealing with these threats. The monsters may come from portals or some form of a dungeon. During the same appearance of these fantastic fiends, humans gain supernatural powers and maybe become connected to an RPG system. These people are counter the threat where sometimes organizations are made to give a coordinated force to ensure the public’s safety. A modern world where monsters and other fantastic elements exist where hostile creatures are not the only problem. Another outcome can be apocalyptic, where the old society is gone, and now only the strong can survive while even thrive in this new world of fantasy. The tropes may act as a Sub-Trope to Urban Fantasy, Just Before the End, or After the End.

Anime and Manga

 * The World Is Overflowing with Monster, I’m Taking a Liking to This Life starts with Kudou Kazuto getting off late from his black company job. As he drives home, he accidentally hits a large dog that dies shortly, which then causes Kazuto to hear a voice stating he has leveled up. The man then returns home and goes to sleep after reading web novels. Kazuto wakes up the next day with no electricity and looks outside to see giant trees growing out of building and monsters roaming the street massacring people. The man then opens up a status window and realizes that he has stats, jobs, and skills like in an RPG. He later learns that other people, animals, and monsters have access to the same RPG system.
 * JK Musou - Owaru Sekai no Sukuikata has monsters start rampaging throughout the world, which leads to civilization decline. The protagonist, a hikikomori girl, learns that she can level up like in an RPG. She also can gain new skills and use magic. She then integrates into a group of people that system they use called ‘Players’. These people can exterminate monsters and save people around them during this cataclysmic time.
 * In Bouken-ka ni Narou!: Skill Board de Dungeon Kouryaku, Dungeons have appeared five years ago around the world where monsters appeared around the world in a massive number. This event has been named ‘The Stampede’. After five years, civilization has bounced back, and the government has issued the job of being an Adventurer. These people venture into dungeons while risking their lives by defeating monsters in them. Adventurers can level up from the XP they gain from killing monsters, which means they get stronger. They can also get various items and equipment that have powers that transcend human knowledge.

Literature

 * System Apocalypse has the titular event cause various creatures such as monsters and aliens to appear on Earth. The world is further devastated with no electricity, but The System can help due to acting like an RPG. This system gives people classes, skills, stats, and equipment for combat. It also provides other services such as functions for buildings and providing necessities if the preconditions are met.

Web Comics
In Solo Leveling, Portals around the world called Gates that connect to another dimension dubbed a Dungeon where monsters termed Magic Beasts. These Magi Beast can come out after seven days of these Gates’ appearance and are predisposed to hunting humans. There are people called Hunters who go through a phenomenon called Awakened, where they gain mysterious magical powers. Even the weakest ranked Hunters have some form of supernatural strength and healing factor. They also have different classes similar to an RPG fantasy, such as fighter, mage, or assassin. Hunters are capable of using their abilities along with equipment to fight monsters outside or in a Dungeon, which can be cleared, thus causes their respective Gate to close. Some Hunters go through Reawakened that can give more strength and powers than their first Awakened. The main character, Sung Jin-Woo, has gone through such a phenomenon where he connects to a mysterious System that allows him to grow in strength by leveling up, gaining new skills, rewards from quests, along with a store where he can buy and sell various items.
 * The setting of 3CM Hunter has everyone in the world has been shrunk down to 3cm, where items like insects, birds, rats, and even doors are dangerous. The people are greeted with windows as if in a game detailing information about the current situation. They also learn about how they get a job and unique ability, which takes their stamina depending on it. Each ability has a level that can be leveled up to become more potent and more efficient. The main character can create barriers, and his job of Prince gives him a map that shows location layout, detect people alive nearby, and can even identify possible hazards nearby. The whole situation is very similar to the web novel his younger sister writes.
 * The webtoon, Solo Login, has the event where ‘Sky Castles’ appears a decade ago around the world that floats in the sky and inaccessible by aircraft. The castles have been selecting humans officially dubbed Players who gain supernatural abilities from mana and wings to fly, especially to the aerial structures. The Players also have access to RPG-like windows. They also have levels, stats, and skills while also being able to level up along with skills and equipment while fighting in dungeons. Sky Castles are filled with dangers from traps to monsters while containing treasures as well. Jung Si-woo sees a Player falling from the sky and captures her, but he did several stories in the air. The two being so high in the air, causing them to fall through the ground where they find an underground Dungeon. After clearing the Dungeon, it’s revealed that Underground Players exist who use a tail to access a Dungeon similar to Sky Players who use their wings.  Later on, monsters from these Underground Dungeons start attacking worldwide, and only Players capable of fighting them.
 * In I am the Sorcerer King, portals called Rifts around the world open that allow countless monsters to come through 10 years ago. Along with the monsters, people called the Awakened are connected to the Ahkasha System regardless of age, gender, and ethnicity. The system is run by the Director of Ahkash and allows the Awakened to access notification windows, acquire a job, level up from experience, grind stats, and gain skills.
 * In Omniscient Reader’s Viewpoint, begins with the web novel, Three Ways to Survive in a Ruined World, ran over 3000 chapters but only 1 reader and comments for a decade, Dokja. After the final chapter been released, he then noticed events that happened through the novel after getting a strange message from the author. Every person then gets screens to appear in front of them detailing the first Scenario with consequences of death if failure is met. The survivors have access to exclusive skills along with a status window like an RPG. They can also level up these unique skills and their stats by spending coins gained from Scenarios. There are also not only other survivors being threats but also deadly monsters as well.
 * Raid (SF) has a setting where a supercomputer has taken over the world by introducing nanomachines around the globe. Everyone has a watch-like device called a Nanocircle, which augments their abilities along with granting equipment. The computer also hands out quests such as killing biomechanical monsters to helping your local community where it hands out rewards to anyone who fulfills them. Modern-day weaponry has also been made obsolete due to the advances brought by Nanocircles.
 * The webtoon of Kill the Hero, on January 1st, 2020, Dungeons have appeared around the world where monsters poured from portals. The monsters have destroyed cities along with killing many people, but then divine beings called Nimbus appeared. They have granted a small number of people with an extraordinary power called the Authority. Those who receive this power awaken to become ‘Players’ that can destroy dungeons. When a person is a Player, they can level up, get notifications related to them, and gain skills depending on the Nimbus that bestowed the Authority.
 * In Raid, 50 years ago, after the Korean War, Demon World Gates has appeared all over the world that opens to the Demon World. Demon crosses these portals, and no modern weaponry couldn’t hurt them. God then granted humans the ability to stand up against, such as threats called a Master. They could fight on par with Demons, along with destroying a Demon World Gate. Masters each have powers that would co-relate to roles found in an MMORPG like Tanker, Melee DPS, Healer, and Support.  Every time a Demon World Gate opens, 10 or more Masters group together to destroy these portals, which has been dubbed Raids.