This is the piece of Shion Sonozaki, who goes mad after being taken in by Rule X.

With no room for sympathy, this is such a painful piece that one can only have pity.

It distinctly identifies the keyhole of the padlock called Rule Z.

Keiichi Maebara becomes a key himself to pry open this padlock.

And as Mion Sonozaki wished for, he becomes a wind that clears out the stagnant air filling the village.

This piece also teaches us an important lesson.

Shion Sonozaki learns through this piece, and then becomes a strong ally for Satoko Houjou.

In that way, maybe Satoko Houjou is a piece that represents the padlock for Rule Z.

Unless she is saved, Rule Z can't be defeated.

And when she is saved, that means Rule Z is defeated.

This piece indicates only that.

That's the only thing Shion Sonozaki learned by gambling her life.

But now, I think that it's very important.

Every time I see Satoko and Shion argue about pumpkins, I think about that.