The supporting character's harem is very normal - Chapter 459 You can do it

Hundreds of years ago, Human, Celestial Clan and Demon Clan lived together on the Origin Continent. However, a great war broke out between the three races. Shan He, the leader of Human, had discovered a catalogue of methods to forge Divine Weapons. With this catalogue, Shan He led Human to defeat the other two clans and expelled them from the Origin Continent.

The peace did not last long. After the passing of Shan He, the once Glory Empire collapsed. Various forces of Human fell into a long period of wild war for the Divine Weapon Catalogue, but the catalogue was lost during the war.

The Demon Clan took advantage of the internal strife of Human. Under the lead of their new lord, Fen Tian, the Demon army invaded the Origin Continent violently.

Human soon lost a large portion of their territory. At that moment, a mysterious hero suddenly appeared on the battlefield. With a legendary Divine Weapon in hand, he severely injured Fen Tian and forced him to retreat. The united Human army chased the Demon army across the strait and to the Two Realm Plain on the Tranquil Continent.

Once again, the various forces of Human started wildly searching for the Divine Weapon Catalogue…

- Description from Novelupdates

The human Race is at war with the Vicious Dalki and when they needed help more than ever, THEY started to come forward.

Humans who had hidden in the shadows for hundreds of years, people with abilities.

Some chose to share their knowledge to the rest of the world in hopes of winning the war, while others kept their abilities to themselves.

Quinn had lost everything to the war, his home, his family and the only thing he had inherited was a crummy old book that he couldn’t even open.

But when the book had finally opened, Quinn was granted a system and his whole life was turned around.

He completed quest after quest and became more powerful, until one day the system gave him a quest he wasn’t sure he could complete.

"It is time to feed!"
"You must drink human blood within 24 hours"
"Your HP will continue to decrease until the task has been completed"

After graduating, Su Jing was met with rejection everywhere he went. Discouraged, he returned home to adjust his mood. He then discovered that his own backyard had become the Galactic Garbage Station. Every day, lots of tr*sh would suddenly appear – some were from Tomb of God, Battle Through the Heavens, Coiling Dragon, One Piece, Naruto, Bleach, X-Men, Captain America, Iron Man, and even from the Marvel Universe. As the owner of the garbage station, Su Jing had the duty to process all these tr*sh. In the beginning, he thought it would be a hard and unprofitable task. Afterwards, he discovered that this was actually the most beautiful and cushy job of his entire life.

As Shin Youngwoo has had an unfortunate life and is now stuck carrying bricks on construction sites. He even had to do labor in the VR game, Satisfy!