Talk:Delvers/@comment-27.142.243.70-20200203105440

So I reread some of the manga and I think I have a pretty good explanation for the discrepency in depth limits. If you read (or watch the anime) from Nanachi's flashback, there's a part where you see Bonedrewd talking to a Black Whistle which was what caused Nanachi to go off running to find Mitty.

Part of this had Bonedrewd saying he specifically pushed for Black Whistles to be allowed down in the fifth layer. So what it would end up being is, the old limits had Black Whistles limited to the 4th layer while Bonedrewd managed to get the limits updated so Black Whistles could go down to the 5th layer (Presumably they updated the Moon Whistle limit as well to match). The first volume is based on the children's understanding based on older maps and books while the second volume gives us the most current up to date information.