Dirks nods his understanding, face unreadable as ever.

[Do you have any art of the Great Whale? Paintings or statues or anything?]

Seems likely for a religion, unless said religion has some kind of stigma against idolatry. The whale they keep mentioning is the piece of the puzzle he doesn't quite know what to do with without more information, and it seems kinda boorish to just outright ask if they're talking about a literal whale or a metaphor for a storm or some kind of actual supernatural being.