I Thought Dumbledore Was a Dungeon Boss

Nearly ten years ago, Witt Cress transmigrated into another world. As far as he could tell, though, there was nothing special about it. it was just ordinary London, so he simply settled down and lived his new life.

Then, Witt suddenly awakened a mysterious Dungeon System. For his very first quest, he spun the roulette wheel and somehow hit a Legendary Dungeon, despite the chance being absurdly small.

[Legendary Quest: The Radiant Twin Emperors]
[Bosses: Grindelwald & Dumbledore]
[Objective: Defeat them.]

Who were Grindelwald and Dumbledore? Witt had absolutely no idea, but surely the System wouldn't give a beginner an impossible quest... right?

So he grabbed his starter wand, entered the dungeon, cast Lumos-
and immediately died... Naturally, he went back the next day.

After hundreds of deaths, countless failed attempts, and enough Killing Curses to make instant death feel strangely comfortable, Witt eventually accepted one simple rule, if you can respawn, dying is just part of grinding.

Then one morning, an owl delivered a letter from somewhere called Hogwarts School of Witchcraft and Wizardry. Witt knew absolutely nothing about it.

But there was one name on the letter he definitely recognized.

Headmaster: Albus Dumbledore Σ(°ロ°).

Witt stared at the letter, packed his suitcase, and ran. Because as far as he was concerned, one of his Legendary Quest bosses had finally tracked him down in the real world.

And so began Witt Cress's completely normal school life, grinding impossible dungeons, collecting ridiculous rewards, meeting legendary people he doesn't recognize, and reaching perfectly logical conclusions based on completely wrong information.

After all, Witt doesn't know he's in Harry Potter or even who is Harry Potter.

He's just winging it (⸝⸝> ᴗ•⸝⸝).