[Well, color him surprised. Will had, in fact, assumed that Kuai's manner of dress was indicative of his time period. Apparently he's just like that. There are eccentrics in every world, it seems.]

This place did have access to some sort of inter-worldly portal, so there is that. Speaking of which, I would assume that to be the method by which the Night Market obtains the things from our world. In which case it would imply they have more mastery over it than Robin does.

... Or at least more than she's willing to use for us.