It is indeed a remake of Etrian Odyssey I. Out of curiosity, are you playing classic or story? Also, what's the name of the last area? (Want to make sure we're on the same page here - not sure if things were changed up too much from the original or if the final area is different in story mode or something)
I don't remember the specifics of the first one (I, not too long ago, finished 100%ing the second game, so that's more fresh in my mind. Plus, after finishing EO I, I took a good long break from EO. >_>) but don't you have access to Theriaca BX (or something like that) that cures ailments? I'm pretty sure there's some item that will cure petrification, though I'll say again that I might be thinking of something only in the second game. >_>
As an aside - I'm 1 trophy from getting the platinum in Dangan Ronpa 2. 
Story Mode and I'm in Claret Hollows, mostly having trouble on Floors 27 and lower. As far as that item, there's one called Theriaca B that does that, but I didn't think it worked on Petrification. I'll give it a try if that happens again.
Main issues have been due to Depth Dancers, Evilroots, Red Corpuscles and Leukocytes. Although I may have the Leukocytes down assuming they don't show up outside of Songbirds summoning in the lower floors.
Evilroots blindsiding my party has been a complete party wipe every time. First time I tried to attack, didn't work as they're somehow faster (or their OHKO the entire party move has priority assuming that exists like in Pokemon), the other two times, I tried running and couldn't of course, despite being in the mid 80s. Running just doesn't seem to ever work in this game. If there was an item that guaranteed it, I'd definitely use it even if it cost 100k en each.
Depth Dancers are really annoying as if you start a fight with one, there's generally another one or two that always come in and I can't take on 2-3 of them at once. Especially with the Demon Beaks they use and summoning those Red Corpuscles that can OHKO anyone. I'm trying Ricochet to see if that helps with them, but I'm not sure if it will. I'm hoping Ricochet can OHKO them as Inferno/Cocytus/Thor Formulas aren't able to due to their elemental resists.
Edited by HylianGlaceon, 24 September 2014 - 12:43 PM.