MTL - The Manga of Ten Thousand Realms - Chapter 180

The Immortal Path led to Longevity and Sovereign was heading in ease. When the Longevity was no longer in ease, all living beings were just prisoners. Conspiracy, internal strife, and the invasion of the others, all of it emerged together. 

In such a world, there was such a young man. He made his way upstream, stepping on blood, defying the emperor, destroying the various kings, and slaughtering his way through the hundred clans to form an Immortal Path towards the throne of Sovereign! The Immortal Path was endless, while the Sovereign was limited. He used his blood to forge his immortal legend.

- Description from Novelupdates

When he was engrossed in the Wizard World, Roger unexpectedly transmigrated to a world that seemed familiar yet strange.In this place, the legendary monsters actually existed, disguising themselves among the populace and becoming a part of this world.Starting from a deserted island, Roger began his career as a Demon Hunter.Although he had an inborn golden touch after transmigrating, what made him somewhat helpless was that it wasn't him with the cheat, but rather just a dilapidated house ready to collapse...After a long time, when Roger ascended to the castle surrounded by mountain peaks,he couldn't help but let out a sincere exclamation:“From a cabin to a castle, the house is too big and hard to manage!”…………This is the story of a Demonic Hunter living in the modern world.

Su Ran, a music prodigy, woke up transmigrated into a book.

At that point in time, the main story arc in the book had already been completed. As a villainess female supporting character, not only did she need to take over the original owner’s pitiful life in poverty, she also gained an instant son right at his rebellious period.

Ten or so more years from then, the son would turn into a twisted, evil villain. He would appear in one of the extra chapters to pick on the male and female lead’s children.

***

Su Ran: Son, you shouldn’t be too outstanding.
Su Han: Why not?
Su Ran: ’cause you will be killed.

Su Ran: Son, would you like to learn music from me and become a zen, little fairy boy who only needs to drink dew.
Su Han: No, I want to go into business so I can support you.

- Description from Novelupdates

Karl Adelheit, a self-proclaimed ordinary student returning from military service.

And a nobleman who enlisted as a soldier and received Medals of Honor.