Surviving in a third-rate martial arts world

Synopsis

I found myself transmigrated into a third-rate martial arts novel, <The Return of the Heavenly Demon>. But not as the protagonist or even the antagonist, just a minor character doomed to a horrible death.
Facing imminent death, I had only one way to survive in this trashy harem martial arts novel.
“Where do you think you’re going?”
I had to keep the overpowered protagonist, Ja-Hyun, at our inn until the guys who would eventually kill me showed up.
“Do you even know how much money you’ve cost me so far? If you want to leave, you have to pay me back for all the food, lodging, and clothing. Trying to sneak away, are you?”
“...”
“You said you have nowhere to go anyway. Why not work here until your memory comes back?”
“...”
“Why... why are you looking at me like that? Our inn is short-staffed, so you might as well stay and do odd jobs.”
Years had passed since I forced the homeless protagonist to stay.
“You still haven’t left?”
“Where would I go?”
“I’m telling you, you don’t owe me anything anymore. Put that ladle down and go your own way.”
“…You idiot. Can’t you even do basic math? You need to pay interest too.”
I no longer had to worry about losing my life. For the sake of peace in the martial world, I decided it was time to let the protagonist go.
But for some reason, he showed no intention of leaving the inn.
...And what’s this? He says he’ll pay three years’ worth of interest with his body?