After a good 2 hours or two organizing people to go, we finally headed out to Dem and shortly after that, into the Promyvion - Dem. The first two floors were easy enough, but we lacked many rangers. I think we just the one that organized the party. Luckily, we had 4 summoners and we took care of the MRs. We reached the MR on the 3rd floor and when It finally died, everyone ran for the portal. Only 10 of us made it.
We snuck by as many monsters as we could on the final floor and eventually had to aggro one with an avatar and flee for the exit. So there was 10 of us. Too many for one party, too few for two.
I talked them into letting me take 2 other summoners (as I am one already.) There was a monk, who secretly had anima, and another white mage left.
Much to my suprize, the boss fight wasn't all that hard. We started with Anima and then the three of us summoners all Astral Flowed for about 1200-1400 damage in total (roughly 50-60% of his HP.) Healed our MP, did it again. Monk used Hundred Fists to finish it. I belive our white mage had to use a single Cure II that entire fight.
My Reccomendation: Get Anima. Get Summoners. Pray.
Good luck :).