Re:Zero Kara Hajimeru Isekai Seikatsu - Chapter 55Arc 7, B - “The Cacophony of the Fortress City”

In childhood, they were neighbors. Xie Zhen always bullied Li Yu.

“Even if this universe is truly nothing more than a brutal bloody shadowy forest, we Cultivators will burn all that we have just to give off a single weak flickering spark in the darkness!

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

Lin Tianlong, 19 years old, a polytechnic school graduate. With mastery and control over electrical energy, he displays his unparalleled sagely medical skills, accepting the hearts of beauties on the side. Starting by helping his sister-in-law’s small clinic which was on the brink of closing down rise from the dead, he then proceeds to bring prosperity to a private hospital previously in a business slump. Socializing among the officials from the sectors of politics, commerce, law, literature, education, and health in Flame City, he’s drawn into the power struggle between the officials. Businesswomen, doctors, and nurses, attractive policewomen, teachers, pretty loli girls, charming married women, mature beauties – all of them fall to his clutches as he establishes his business empire and a harem of beautiful women.

- Description from Novelupdates