Weren't You Going to Join Me in Defeating the Demon King?

I'm Ron, and I have a sister who's always coming up with bizarre ideas. Her name is Luo Yu, and she's been going on about the Demon King and the Hero since she was little. But, "Where would demons get a king?! Sis? And what's a holy sword? What do you mean it's a convention in a Western fantasy setting?!"

Under pressure from my sister, I had no choice but to join her on an adventure. But what's with this lecherous elf? And why is there a princess who ran away from home? At least there's a soft, squishy priestess to comfort me.

But when you joined the party, didn't you say you wanted to help us defeat the Demon King? Why are you looking at me like that now!!! I'm not food!

Sis! Save me!

Wait, what? Sis?! What are you doing? Why are you tying me up? What do you mean hiding me away will solve all these problems?!

Nooooo!!!