Due to the fact that Choso spent most of his long life in the company of curses rather than people, his knowledge of them was not great.

Especially knowledge about women's physiology.

That's why he was surprised when he found out about menstruation. He practically panicked when he heard from you, his girlfriend, what you go through every month.

"What?! You bleed for a few days every month and this is supposed to be normal?!" He exclaimed, almost outraged at biology and the world for how you have to suffer.