The supporting character's harem is very normal - Chapter 461 Karol Magic Academy.

have you heard of it?

If you turn on the music player in the dead of night, put on headphones, hide your head in the quilt, and listen to the looped single repeatedly.

Fall asleep after looping forty-four times. If you are unlucky and open your eyes again, you will no longer be lying on your own bed, but will enter a strange space that is completely isolated from reality.

That space… On the surface, it looks like the places we usually see, such as our bedroom, living room at home, underground garage, bathroom, basketball court, construction site, etc. But if you look closely, you will find that it is different. …Everything is different.

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This is the experience of an ordinary person who, after acquiring superpowers, transforms and grows step by step in a blind corner, reaching the ultimate level.

- Description from novelbuddy

When the system warned the world that it was coming a week in advance, Alex couldn’t have been more excited. In college for a degree he didn’t care about to get a job he didn’t want, the promise of a world where magic and challenge awaited — even at the potential cost of death — was the best news he possibly could have imagined. Alex was ready for a new life. He ready for his only friend to shove him through a portal into hell the moment the apocalypse started. Instead of getting to punt rabbits and farm wolves, Alex finds himself stranded in a warped world where even the bugs are stronger than he is. Even with a summoner class that gains the powers of its monsters, most people would have died. Alex didn’t get the memo. He might have liked challenge a little bit too much. Where others saw certain death, he found something else. Opportunity.

Lin Wudao transmigrated and obtained an invincible system to bury corpses.

So long as he buried the corpses of the powerful, he got to take over what they had or what they touched as his bonus. What was more, those items he stood to win were the enhanced versions.

The minimum level was enhanced by ten times!

“You’ve buried the corpse of Jiang Taichu the Great Emperor. Your cultivation prowess just increased by 10,000 years!”

“You’ve buried the corpse of your fiancee, Jiang Qingxue. You get the essence of the immortal, which is enhanced by 100,000 times! It’s thus upgraded into the essence of harmony. You will become the Immortal Emperor after the extraction of it!”

……

Ever since he acquired this system, Lin Wudao had embarked on an invincible journey of advancing history and dominating the world.

Chu Li was a particle physicist until a freak accident took his life and transmigrated him to a parallel universe – one where he wakes up with inexplicable abilities and finds himself in the running for a job in the imperial palace.

This is a story of heroic adventures, cunning strategies and romantic tales. How will our MC thrive in a world completely strange to him? Where will his ambitions and abilities take him in the palace?