Dungeon Battle Royale ~ Since I became a Demon King, I will aim for World Domination - Chapter ex1: Extra – Timeline

Spiritual energy ecovery brought about fundamental changes throughout the entire world, and posed an imminent threat to it. Chen Yang died in an accident and reincarnated to become a tiny koi fish inside the fish tank in his own home. Just as Chen Yang complained about the unfairness of destiny, he awakened the Evolution System. Thus, with his sister’s feeding, Chen Yang started his insane evolution. As the whole world sank deep into apocalypse, Chen Yang descended from the skies to crush everything.

He had evolved from a tiny koi fish to a gargantuan dragon. “This world shall be ruled by me!” When the fish playing in the waters was frightened by the net, it jumped over the Dragon’s Gate to become a real dragon. This is a story of how a loli raised a giant dragon, and dominated everything.

Baek Ain is your typical lazy guy.

He graduated from university at age 22 with a random degree he chose out of boredom and stayed single because fate decided so until that event happened.

“What? Where Am I??”

After a horrible incident, Ain transmigrated to another world. Or precisely to be a villainous and mobs character.

He died countless times because of the world's protagonists, gathering hatred toward them.

“What the fuck! What do you mean I stole your wife? I've been single since coming into this world!!”

“Hero, please save this world.” A goddess is begging me to save her world from the Demon Lord.

“Wait... Begone thot! That Demon King is my younger sister from 69th Transmigration.”

“How dare you!”

A beautiful heroine is hugging me from behind, wishing to accept her feelings.

“Shoo, Heroine! I don't need useless baggage with me. Side characters are better than you!”

And so, Ain's journey began to end this shitty transmigration cycle.

On the battlefield, the Avengers fell into a bitter battle, and when Thanos was about to win, suddenly, there was a loud noise in the sky, and only a huge battleship that covered the sky appeared above everyone’s heads, and opened the door from the battleship. A man stepped out of the hatch.

“who are you!”

Thanos felt uneasy and shouted loudly.

“Who am I, you ask?”

The man looked down on the world.

“Listen well, I am the doctor of Rhodes Island, the admiral of the tutelary mansion, the master of Chaldea, the commander of Griffin, the onmyoji of Heianjing, the knight of Princess Link, the dress-up master of the Miracle Continent, Rainbow Squad operator, Battle Commander, Duelist of Dueling City, Demon Hunter who can cry, Demon Hunter who collects Gwent cards, Ashes of No Fire, Master Ashes of Fireproof Lady, Destroyer of Outer Gods. Sever Undead The man of the sky. Grabber of Skyrim, god of war who slaughtered the gods of Olympus and Asgard. Assassin who wants nothing but love, little policeman of Raccoon City, ruler and protector of the border. King of Erden, High Lord of Azeroth, Warrior of Arad, Summoner of Valoran, Defender of Crossfire, Mercenary of Kuhan…”

- Description from novelbuddy

15 years ago the world discovered magic as well as mythical beings (basically beings from various legends) in another dimension. Humankind learned to summon these dangerous mythical beings and use their power to great effect. Seven countries formed contracts with these “mythical beings” and gained their allegiance as a result. The mythical beings will choose their summoners on their 14th birthday and give them a stigma. Schools have been set up to train summoners and magical swordsman (basically bodyguards that give the summoners time to cast their spell) as a result.

15 years later after the finding of magic Kazuki Hayashizaki is chosen as a summoner and given a stigma to indicate that. This is surprising since males aren’t chosen as summoners due to their low amount of mana compared to females. As the first male to be a summoner Kazuki is under a lot of scrutiny by almost everyone.

To complicate matters his sister (who’s a magical swordsman) is against him going into summoner school to train there as a summoner. Because summoners and magical swordsman have a cat mouse thing going on where summoners look down on magical swordsman as inferior so his sister naturally is against him going there. She’ll stop him even if it means going to war.

Kazuki however is determined to thrive in summoner school and has already determined to give it his all. Even if he’s the lowest ranked student (ranked E) and his fellow students intend to demean him he’ll prove himself as the strongest summoner.