Thread:Reapertmn3/@comment-22439-20150912194740/@comment-4784862-20150918042543

hrm...Velvet's Dungeon is the first dungeon I think (though it's not a dungeon in the way that the other dungeons are)...and that's around Day 37 iirc.

If you're talking about the dungeons like the ones in Purgatory and whatnot...then...well...I think the first one is mentioned somewhere between Day 90 and Day 110...because it's mentioned that Kichi enters it (though I don't think we know its name...though it might be in the sidestory about his ranking up and whatnot).