Nayu and Karen aren't even close to be on the same page. I'm really curious to see where the story goes, but I'm pretty sure Nayu's feelings will be crushed hard.
Thanks for the chapter
Anyway, is always nice to read a slice of life / fanservice / comedy chapter, these are the best ones. That said, I'm pretty sure this is a foreshadowing and the oil will be useful somehow on the upcoming Demon Lord arc.
Thanks for the chapter.