The Marriage of an Esteemed Supreme Healer, a Noble Ruler - Chapter 2532 - Side Story 36: Efficiency

The countries of Mephius and Garbera have been waging a war for ten years and are trying to put an end to this long fight through a political marriage between the two royal families. Orba, who was driven from his home because of the war and was forced to become a gladiator, looks exactly like the crown prince of Mephius, and it has been decided he will be substituting him during the wedding ceremony. On the other hand, Vileena, the princess of Garbera, has secretly decided to ensnare the crown prince for her own country’s interests.

The protagonist travels through Shu Mountain and becomes a demonic dragon guarding the heavenly book in Dinghu Peak.

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!
With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

- Description from Novelupdates

The world is up for sale, and Robin is making an offer.When Robin Waybright became the Merchant Hero, all of Pangeal turned into his marketplace; for the Merchant can buy and sell anything. Youth, skills, memories, hair color, joys and illnesses… in the trade of power, every deal can tip the scale.And Robin needs power. His homeland of Archfrost teeters on the brink of collapse, the sinister Demon Ancestors plot in the shadows, and twenty-one other Heroes, each with their own Class, have been chosen to save the world of Pangeal. Not all of them are friendly. There’s work to do… and profit to make.Cover by Dinovoila and Gharbi Zouhayer.