I Transmigrated Then Switched Parents With the Villain

‘I transmigrated to another world.’
However, it was the world of the R-rated tragedy novel, ‘The Black-Haired Healer’.
What’s worse, I became a minor character who was the ‘younger brother’s substitute’ for the disabled villain, and who ultimately ended up being executed.
Realizing this fact, Shushu fled to the North with his mother.
But even a seven-year-old Shushu could not twist the original plot, and he eventually became the substitute for Damian Vesper…
No matter how hard he tried to keep his identity hidden—
“Take them off.”
When Shushu turned twenty, the villain’s older brother, Calix Vesper, began to suspect him.
“Take them off, Shushu. If you don’t take your clothes off yourself, I’ll call a servant to strip you.”
He knew that the day would come when his true identity would be exposed, so the first thing he did every morning was to cover up the ‘name’ engraved on his body with makeup.
Finally, his collar parted, revealing white skin that looked as if it had never seen sunlight.
Calix’s Adam’s apple bobbed violently.
‘My jewel, my Omega. My Shushu!’
The man’s hand, calloused and hardened by rigorous sword training, slowly stroked Shushu’s body.
After a careful inspection, Calix finally took his hand away.
Just as Shushu was secretly letting out a sigh of relief, Calix pulled a handkerchief from his jacket and rubbed Shushu’s shoulder blades.
The ‘name,’ which had been concealed by makeup, was finally revealed.
‘Calix Vesper.’
It was the perfect brand, marking him as his male-born mate.