Transmigrate inside a Web Novel as a Side Character. - Chapter 343 - Leaving.

In the age of the Great Liang Dynasty, the lives of the people were made convenient with steam-powered machines that run on a fuel named Violetstream Gold. Chang Geng, who lived in a small countryside village, shared a distant relationship with his mother while his stepfather was away most of the year round, and the only people he was close to were two little kids, the village teacher, and his yi fu – adoptive father. But his life was flipped upside down one day following the barbaric Man tribes’ invasion, and it turned out that his entire identity had been an illusion – not only was Chang Geng himself not the country boy he thought he was, but also his mother, his teacher, and even his beloved yi fu…

- Description from Novelupdates

I had been abroad to do medical volunteer work, when I was swept up in a civil war. I was killed by a rebel soldier, while taking a bullet for a patient. But when I finally woke up, I had become a child?!?And in front of me stood a destroyed carriage and a group of oddly dressed people, who were unconscious!“It’s just like a Murim world.”As I hurry to perform first aid in an attempt to save even one person, I realize that this world is that of [The Supreme Demon King], a Wuxia novel I’ve enjoyed reading.After meeting the rescue team of the ‘Three Great Doctors’, I found out that one of the person I saved was the protagonist of this novel, the future Demon King ‘Yeo Haryun’!“Hey, since I’m indebted to you for saving me, call me ‘hyung’.”For saving his life, I become sworn brothers with the future Demon King, and the White Dragon Godly Doctor, one of the most knowledgeable people around, recognized my potential and took me in as his disciple. This is the story of how I became the greatest physician in Gangho!

Travel to the world of pirates and become Belmer’s adopted son! Nami and Nokigo’s older brother! Liu Ye, has been planting oranges for five years!

One day, Liu Ye, who suddenly realized that he couldn’t go on like this, with the mentality of trying, meditated in his heart: “System?”

“I’m here.” A cute voice like classmate Xiao Ai rang.

Awaken the strongest clone system! Every time you level up, you can get a clone!

Absolute loyalty, not afraid of death, and able to upgrade through battles, improve attributes, and even directly buy various exaggerated magical abilities!

“To tell you the truth, the naval headquarters, the sea emperor of the new world, the master of the underground world, and even the top leaders of the cp0 and the revolutionary army, have my people.”

Before the war in Wano, Liu Yejin took Nami’s hand mysteriously, and said to Nami, “Don’t be afraid, no one dares to touch you with your brother’s backing.”

- Description from novelbuddy

Another entry in what you can call the Proto Harem Series: the books written before the Harem Series that take place in the same world.

It’s about a swordswoman whose student is captured, so she goes to rescue her.