Tomodachi no Imouto ga Ore ni Dake Uzai - Volume 1, Extra

This novel is also known as Farming And Learning Martial Arts To Bring Peace

The world is difficult and dangerous. Chi Qiaosong’s family has only three acres of thin fields, but he allowed him to grow a splendid world.

…

Two? Two new stories, Bai Yuhan worked hard to conceive, please watch.

- Description from novelbuddy

She was a peerless genius in the way of medicine, holding the Medicine King Cauldron in her hand.

Once she transmigrated, she became a lowly little medicine slave in dispensary.

Physicians made her life difficult, princesses humiliated her, even her fiancé came knocking on her door to break off the engagement?

What was that?!

However, she had the cauldron in her hand; the top-notch medicinal herb was in her hands. She stole rare and precious herbs, punished the slanderous, plotted against the petty, treated the Emperor’s sickness, and saved the Crown Prince.

Then, the imperial edict turned the medicine slave to a concubine and received endless doting. It was unbreakable. Wait… didn’t Prince Jun, who wielded great power in the imperial court, say she was a a detestable individual?

As the saying goes, the concubine was good in the way of medicine.

However…

- Description from Novelupdates

In a galaxy ruled by warlords, guilds, and ancient tech cults, Kai Zareth is just another debt-ridden scavenger—until a legendary system descends upon him.“One Trader per 10,000 light years. One chance to rise.”Selected by the Cosmic Trade Nexus, Kai becomes the sole wielder of the Galactic Exchange System, a multidimensional platform that allows him to buy and sell across parallel worlds, forgotten realms, and alien civilizations.With only 12 hours to complete his first trade—or lose everything—Kai scrambles to make deals in a universe where information is power and one wrong barter could cost your life.From selling enchanted goblin toothbrushes in toxic slums to outwitting rival system users and forging alliances with forgotten races, Kai must build his empire item by item, realm by realm.But in a galaxy where traders kill for profit and system users are hunted like prey, being the Merchant Sovereign might be a bigger curse than a blessing.

His legendary class is The Husband Of Deathwill Sisters!

While other players went through common quests to get their classes, Alex started by getting a legendary class: Husband Of Deathwill Sisters! He got three beautiful wives from the start and the legendary castle!
What would his girlfriend and friends say about this once he reveals his class to them?
And what about Deathwill Sisters? What is their plight, and why would they suddenly get a husband?