I Became the Villain’s Master

Read Manhwa I Became the Villain’s Master / 악역의 주인님이 되었다 / How to Tame the Merciless Villain / I Became the Master of the Villain
After spending 20 years as a slave, the male protagonist turns dark and destroys the empire. Unfortunately, I ended up possessing the body of an extra character who gets killed by that villainous protagonist.
To survive, I must take care of the protagonist with love and dedication before he awakens as a mage and turns dark.
“If it’s you, I don’t mind being used as much as you want.”
“I belong to my master, so you can command me to do anything… but I cannot obey an order to leave.”
What should I do now?
It seems like the protagonist has turned into a possessive man.