One Piece: Don't Worry, I'm a Doctor - Chapter 15 - : Are You Crazy?

Crying blood and tears, she pledged a poisonous vow. The gods did not fail her. She was sent back to a decade ago. The legitimate daughter of Jiang family returned from hell.

I never thought I could become a hunter.I never thought I would get the chance.But that wasn’t true.「 ‘Tower of Trials’ has selected all suitable candidates from Earth. 」「 Please select your difficulty. 」「The chosen difficulty will be directly proportional to your rewards. 」I was given a chance now.A special one at that.

Six months ago, tens of thousands of black phantom towers appeared all over the world, floating above the cities. Chemists, physicists, religious people… all of them could do nothing.

Six months later, people became used to the towers and no longer paid them attention.

One day, Tang Mo saw a flying insect crash into it instead of going through it. The next day, a sharp and clear child-like voice issued an announcement to all humans.

“Ding dong! November 15th, 2017. The earth is online.”

The black tower’s three iron-clad rules:

1. Everything is explained by the black tower.

2. 6 o’clock to 18 o’clock is the game time.

3. All players, please strive to attack the tower.

- Description from Novelupdates

Talented in Magecraft but useless in physical combat?